mirror of
https://github.com/jashkenas/coffeescript.git
synced 2022-11-09 12:23:24 -05:00
b192e215a5
* Output simple array destructuring assignments to ES2015 * Output simple object destructured assignments to ES2015 * Compile shorthand object properties to ES2015 shorthand properties This dramatically improves the appearance of destructured imports. * Compile default values in destructured assignment to ES2015 * Rename `wrapInBraces` to `wrapInParentheses`, and `compilePatternMatch` to `compileDestructuring`, for clarity; style improvements (no `==` or `!=`, etc.) * Don’t confuse the syntax highlighter * Comment Assign::compilePatternMatch a bit * Assignment expressions in conditionals are a bad practice * Optional check for existence that only checks `!== undefined`, not `!= null`, to follow ES convention that default values only apply when a variable is undefined, not falsy * Add comments; remove unnecessary array splats in function tests * The fallback destructuring code should apply default values only if `undefined`, not falsy, to follow ES spec * Support destructuring in function parameters (first pass); catch destructured reserved words * Destructured variables in function parameter lists shouldn’t be added to the function body with `var` declarations; treat splat array function parameters the legacy way to avoid rethinking #4005 * Remove redundancy in undefined-only check for existence; fix passing option to check * Fix undefined redundancy * Simplify getting the variable name * Reimplement “check for existence if not undefined” without creating a new operator * `Obj::isAssignable` should not mutate; pass `lhs` property in from `Assign` or `Code` to child arrays and objects so that those child nodes are set as allowable for destructuring * Revert changes to tests * Restore revised test for empty destructuring assignment
364 lines
9.2 KiB
CoffeeScript
364 lines
9.2 KiB
CoffeeScript
# Function Literals
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# -----------------
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# TODO: add indexing and method invocation tests: (->)[0], (->).call()
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# * Function Definition
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# * Bound Function Definition
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# * Parameter List Features
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# * Splat Parameters
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# * Context (@) Parameters
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# * Parameter Destructuring
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# * Default Parameters
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# Function Definition
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x = 1
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y = {}
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y.x = -> 3
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ok x is 1
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ok typeof(y.x) is 'function'
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ok y.x instanceof Function
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ok y.x() is 3
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# The empty function should not cause a syntax error.
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->
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() ->
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# Multiple nested function declarations mixed with implicit calls should not
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# cause a syntax error.
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(one) -> (two) -> three four, (five) -> six seven, eight, (nine) ->
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# with multiple single-line functions on the same line.
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func = (x) -> (x) -> (x) -> x
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ok func(1)(2)(3) is 3
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# Make incorrect indentation safe.
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func = ->
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obj = {
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key: 10
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}
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obj.key - 5
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eq func(), 5
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# Ensure that functions with the same name don't clash with helper functions.
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del = -> 5
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ok del() is 5
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# Bound Function Definition
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obj =
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bound: ->
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(=> this)()
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unbound: ->
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(-> this)()
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nested: ->
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(=>
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(=>
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(=> this)()
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)()
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)()
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eq obj, obj.bound()
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ok obj isnt obj.unbound()
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eq obj, obj.nested()
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test "even more fancy bound functions", ->
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obj =
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one: ->
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do =>
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return this.two()
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two: ->
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do =>
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do =>
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do =>
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return this.three
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three: 3
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eq obj.one(), 3
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test "arguments in bound functions inherit from parent function", ->
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# The `arguments` object in an ES arrow function refers to the `arguments`
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# of the parent scope, just like `this`. In the CoffeeScript 1.x
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# implementation of `=>`, the `arguments` object referred to the arguments
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# of the arrow function; but per the ES2015 spec, `arguments` should refer
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# to the parent.
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arrayEq ((a...) -> a)([1, 2, 3]), ((a...) => a)([1, 2, 3])
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parent = (a, b, c) ->
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(bound = =>
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[arguments[0], arguments[1], arguments[2]]
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)()
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arrayEq [1, 2, 3], parent(1, 2, 3)
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test "self-referencing functions", ->
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changeMe = ->
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changeMe = 2
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changeMe()
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eq changeMe, 2
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# Parameter List Features
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test "splats", ->
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arrayEq [0, 1, 2], (((splat...) -> splat) 0, 1, 2)
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arrayEq [2, 3], (((_, _1, splat...) -> splat) 0, 1, 2, 3)
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arrayEq [0, 1], (((splat..., _, _1) -> splat) 0, 1, 2, 3)
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arrayEq [2], (((_, _1, splat..., _2) -> splat) 0, 1, 2, 3)
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test "destructured splatted parameters", ->
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arr = [0,1,2]
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splatArray = ([a...]) -> a
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splatArrayRest = ([a...],b...) -> arrayEq(a,b); b
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arrayEq splatArray(arr), arr
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arrayEq splatArrayRest(arr,0,1,2), arr
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test "@-parameters: automatically assign an argument's value to a property of the context", ->
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nonce = {}
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((@prop) ->).call context = {}, nonce
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eq nonce, context.prop
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# allow splats along side the special argument
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((splat..., @prop) ->).apply context = {}, [0, 0, nonce]
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eq nonce, context.prop
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# allow the argument itself to be a splat
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((@prop...) ->).call context = {}, 0, nonce, 0
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eq nonce, context.prop[1]
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# the argument should not be able to be referenced normally
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code = '((@prop) -> prop).call {}'
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doesNotThrow -> CoffeeScript.compile code
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throws (-> CoffeeScript.run code), ReferenceError
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code = '((@prop) -> _at_prop).call {}'
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doesNotThrow -> CoffeeScript.compile code
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throws (-> CoffeeScript.run code), ReferenceError
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test "@-parameters and splats with constructors", ->
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a = {}
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b = {}
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class Klass
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constructor: (@first, splat..., @last) ->
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obj = new Klass a, 0, 0, b
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eq a, obj.first
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eq b, obj.last
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test "destructuring in function definition", ->
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(([{a: [b], c}]...) ->
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eq 1, b
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eq 2, c
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) {a: [1], c: 2}
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context = {}
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(([{a: [b, c = 2], @d, e = 4}]...) ->
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eq 1, b
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eq 2, c
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eq @d, 3
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eq context.d, 3
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eq e, 4
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).call context, {a: [1], d: 3}
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(({a: aa = 1, b: bb = 2}) ->
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eq 5, aa
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eq 2, bb
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) {a: 5}
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ajax = (url, {
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async = true,
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beforeSend = (->),
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cache = true,
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method = 'get',
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data = {}
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}) ->
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{url, async, beforeSend, cache, method, data}
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fn = ->
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deepEqual ajax('/home', beforeSend: fn, method: 'post'), {
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url: '/home', async: true, beforeSend: fn, cache: true, method: 'post', data: {}
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}
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test "#4005: `([a = {}]..., b) ->` weirdness", ->
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fn = ([a = {}]..., b) -> [a, b]
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deepEqual fn(5), [{}, 5]
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test "default values", ->
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nonceA = {}
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nonceB = {}
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a = (_,_1,arg=nonceA) -> arg
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eq nonceA, a()
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eq nonceA, a(0)
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eq nonceB, a(0,0,nonceB)
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eq nonceA, a(0,0,undefined)
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eq null, a(0,0,null) # Per ES2015, `null` doesn’t trigger a parameter default value
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eq false , a(0,0,false)
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eq nonceB, a(undefined,undefined,nonceB,undefined)
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b = (_,arg=nonceA,_1,_2) -> arg
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eq nonceA, b()
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eq nonceA, b(0)
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eq nonceB, b(0,nonceB)
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eq nonceA, b(0,undefined)
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eq null, b(0,null)
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eq false , b(0,false)
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eq nonceB, b(undefined,nonceB,undefined)
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c = (arg=nonceA,_,_1) -> arg
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eq nonceA, c()
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eq 0, c(0)
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eq nonceB, c(nonceB)
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eq nonceA, c(undefined)
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eq null, c(null)
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eq false , c(false)
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eq nonceB, c(nonceB,undefined,undefined)
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test "default values with @-parameters", ->
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a = {}
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b = {}
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obj = f: (q = a, @p = b) -> q
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eq a, obj.f()
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eq b, obj.p
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test "default values with splatted arguments", ->
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withSplats = (a = 2, b..., c = 3, d = 5) -> a * (b.length + 1) * c * d
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eq 30, withSplats()
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eq 15, withSplats(1)
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eq 5, withSplats(1,1)
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eq 1, withSplats(1,1,1)
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eq 2, withSplats(1,1,1,1)
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test "#156: parameter lists with expansion", ->
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expandArguments = (first, ..., lastButOne, last) ->
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eq 1, first
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eq 4, lastButOne
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last
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eq 5, expandArguments 1, 2, 3, 4, 5
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throws (-> CoffeeScript.compile "(..., a, b...) ->"), null, "prohibit expansion and a splat"
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throws (-> CoffeeScript.compile "(...) ->"), null, "prohibit lone expansion"
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test "#156: parameter lists with expansion in array destructuring", ->
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expandArray = (..., [..., last]) ->
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last
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eq 3, expandArray 1, 2, 3, [1, 2, 3]
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test "#3502: variable definitions and expansion", ->
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a = b = 0
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f = (a, ..., b) -> [a, b]
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arrayEq [1, 5], f 1, 2, 3, 4, 5
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eq 0, a
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eq 0, b
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test "variable definitions and splat", ->
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a = b = 0
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f = (a, middle..., b) -> [a, middle, b]
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arrayEq [1, [2, 3, 4], 5], f 1, 2, 3, 4, 5
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eq 0, a
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eq 0, b
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test "default values with function calls", ->
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doesNotThrow -> CoffeeScript.compile "(x = f()) ->"
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test "arguments vs parameters", ->
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doesNotThrow -> CoffeeScript.compile "f(x) ->"
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f = (g) -> g()
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eq 5, f (x) -> 5
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test "reserved keyword as parameters", ->
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f = (_case, @case) -> [_case, @case]
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[a, b] = f(1, 2)
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eq 1, a
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eq 2, b
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f = (@case, _case...) -> [@case, _case...]
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[a, b, c] = f(1, 2, 3)
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eq 1, a
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eq 2, b
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eq 3, c
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test "reserved keyword at-splat", ->
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f = (@case...) -> @case
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[a, b] = f(1, 2)
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eq 1, a
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eq 2, b
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test "#1574: Destructuring and a parameter named _arg", ->
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f = ({a, b}, _arg, _arg1) -> [a, b, _arg, _arg1]
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arrayEq [1, 2, 3, 4], f a: 1, b: 2, 3, 4
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test "#1844: bound functions in nested comprehensions causing empty var statements", ->
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a = ((=>) for a in [0] for b in [0])
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eq 1, a.length
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test "#1859: inline function bodies shouldn't modify prior postfix ifs", ->
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list = [1, 2, 3]
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ok true if list.some (x) -> x is 2
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test "#2258: allow whitespace-style parameter lists in function definitions", ->
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func = (
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a, b, c
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) -> c
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eq func(1, 2, 3), 3
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func = (
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a
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b
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c
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) -> b
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eq func(1, 2, 3), 2
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test "#2621: fancy destructuring in parameter lists", ->
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func = ({ prop1: { key1 }, prop2: { key2, key3: [a, b, c] } }) ->
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eq(key2, 'key2')
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eq(a, 'a')
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func({prop1: {key1: 'key1'}, prop2: {key2: 'key2', key3: ['a', 'b', 'c']}})
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test "#1435 Indented property access", ->
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rec = -> rec: rec
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eq 1, do ->
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rec()
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.rec ->
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rec()
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.rec ->
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rec.rec()
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.rec()
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1
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test "#1038 Optimize trailing return statements", ->
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compile = (code) -> CoffeeScript.compile(code, bare: yes).trim().replace(/\s+/g, " ")
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eq "(function() {});", compile("->")
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eq "(function() {});", compile("-> return")
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eq "(function() { return void 0; });", compile("-> undefined")
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eq "(function() { return void 0; });", compile("-> return undefined")
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eq "(function() { foo(); });", compile("""
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->
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foo()
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return
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""")
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test "#4406 Destructured parameter default evaluation order with incrementing variable", ->
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i = 0
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f = ({ a = ++i }, b = ++i) -> [a, b]
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arrayEq f({}), [1, 2]
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test "#4406 Destructured parameter default evaluation order with generator function", ->
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current = 0
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next = -> ++current
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foo = ({ a = next() }, b = next()) -> [ a, b ]
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arrayEq foo({}), [1, 2]
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test "Destructured parameter with default value, that itself has a default value", ->
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# Adapted from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
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draw = ({size = 'big', coords = {x: 0, y: 0}, radius = 25} = {}) -> "#{size}-#{coords.x}-#{coords.y}-#{radius}"
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output = draw
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coords:
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x: 18
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y: 30
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radius: 30
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eq output, 'big-18-30-30'
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