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is_enumerable := func(x) {
return is_array(x) || is_map(x) || is_immutable_array(x) || is_immutable_map(x)
}
is_array_like := func(x) {
return is_array(x) || is_immutable_array(x)
}
export {
// all returns true if the given function `fn` evaluates to a truthy value on
// all of the items in `x`. It returns undefined if `x` is not enumerable.
all: func(x, fn) {
if !is_enumerable(x) { return undefined }
for k, v in x {
if !fn(k, v) { return false }
}
return true
},
// any returns true if the given function `fn` evaluates to a truthy value on
// any of the items in `x`. It returns undefined if `x` is not enumerable.
any: func(x, fn) {
if !is_enumerable(x) { return undefined }
for k, v in x {
if fn(k, v) { return true }
}
return false
},
// chunk returns an array of elements split into groups the length of size.
// If `x` can't be split evenly, the final chunk will be the remaining elements.
// It returns undefined if `x` is not array.
chunk: func(x, size) {
if !is_array_like(x) || !size { return undefined }
numElements := len(x)
if !numElements { return [] }
res := []
idx := 0
for idx < numElements {
res = append(res, x[idx:idx+size])
idx += size
}
return res
},
// at returns an element at the given index (if `x` is array) or
// key (if `x` is map). It returns undefined if `x` is not enumerable.
at: func(x, key) {
if !is_enumerable(x) { return undefined }
if is_array_like(x) {
if !is_int(key) { return undefined }
} else {
if !is_string(key) { return undefined }
}
return x[key]
},
// each iterates over elements of `x` and invokes `fn` for each element. `fn` is
// invoked with two arguments: `key` and `value`. `key` is an int index
// if `x` is array. `key` is a string key if `x` is map. It does not iterate
// and returns undefined if `x` is not enumerable.
each: func(x, fn) {
if !is_enumerable(x) { return undefined }
for k, v in x {
fn(k, v)
}
},
// filter iterates over elements of `x`, returning an array of all elements `fn`
// returns truthy for. `fn` is invoked with two arguments: `key` and `value`.
// `key` is an int index if `x` is array. `key` is a string key if `x` is map.
// It returns undefined if `x` is not enumerable.
filter: func(x, fn) {
if !is_array_like(x) { return undefined }
dst := []
for k, v in x {
if fn(k, v) { dst = append(dst, v) }
}
return dst
},
// find iterates over elements of `x`, returning value of the first element `fn`
// returns truthy for. `fn` is invoked with two arguments: `key` and `value`.
// `key` is an int index if `x` is array. `key` is a string key if `x` is map.
// It returns undefined if `x` is not enumerable.
find: func(x, fn) {
if !is_enumerable(x) { return undefined }
for k, v in x {
if fn(k, v) { return v }
}
},
// find_key iterates over elements of `x`, returning key or index of the first
// element `fn` returns truthy for. `fn` is invoked with two arguments: `key`
// and `value`. `key` is an int index if `x` is array. `key` is a string key if
// `x` is map. It returns undefined if `x` is not enumerable.
find_key: func(x, fn) {
if !is_enumerable(x) { return undefined }
for k, v in x {
if fn(k, v) { return k }
}
},
// map creates an array of values by running each element in `x` through `fn`.
// `fn` is invoked with two arguments: `key` and `value`. `key` is an int index
// if `x` is array. `key` is a string key if `x` is map. It returns undefined
// if `x` is not enumerable.
map: func(x, fn) {
if !is_enumerable(x) { return undefined }
dst := []
for k, v in x {
dst = append(dst, fn(k, v))
}
return dst
},
// key returns the first argument.
key: func(k, _) { return k },
// value returns the second argument.
value: func(_, v) { return v }
}
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