feat: Map support constructor initialization with MapInitialEntries #2941
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- Added new type alias `MapInitialEntries<K, V>` = { key: K, value: V }[]
- Map constructor now accepts:
• An array of { key, value } objects
• Any array typed as MapInitialEntries<K,V>
- This allows populating a Map in one step with strong typing.
- Example:
let myMap = new Map<string, i32>([
{ key: "a", value: 1 },
{ key: "b", value: 2 },
]);
let init: MapInitialEntries<string, i32> = [
{ key: "x", value: 10 },
{ key: "y", value: 20 },
];
let anotherMap = new Map<string, i32>(init);
std/assembly/map.ts
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| if(entriesLength > 0) { | ||
| if(entriesLength >= this.entriesCapacity) this.bucketsMask = entriesLength; | ||
| this.rehash((this.bucketsMask << 1) | 1); | ||
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| for(let i = 0; i < entriesLength; i++){ |
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| if(entriesLength > 0) { | |
| if(entriesLength >= this.entriesCapacity) this.bucketsMask = entriesLength; | |
| this.rehash((this.bucketsMask << 1) | 1); | |
| for(let i = 0; i < entriesLength; i++){ | |
| if (entriesLength > 0) { | |
| if (entriesLength >= this.entriesCapacity) this.bucketsMask = entriesLength; | |
| this.rehash((this.bucketsMask << 1) | 1); | |
| for (let i = 0; i < entriesLength; i++) { |
pebrianz
changed the title
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the test rt/flags failed to compile, when pass type v128 to the map. it need simd to be enabled. Do you have any suggestion? |
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For update all fixtures, try to run |
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This seems acceptable, since we don't have tuples or iterables/iterators. (If/when we do add support for tuples, we would replace this mechanism as a breaking change.) I don't know if we should be concerned about the size increase in symbol.release.wat.
See additional comments below.
std/assembly/map.ts
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| constructor() { | ||
| /* nop */ | ||
| constructor(initialEntries: MapInitialEntries<K,V> = []) { |
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This should be nullable, and the default argument should be null instead of []. Tip: if you wrap the entire constructor body with if (initialEntries) {, you can avoid doing initialEntries!.
(I wonder if this change could be beneficial for code that never uses this feature, by making it easier for Binaryen to optimize)
std/assembly/map.ts
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| private entriesCount: i32 = 0; | ||
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| constructor(initialEntries: MapInitialEntries<K,V> = []) { | ||
| let entriesLength = initialEntries.length; |
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plz revert this cached entriesLength var and use instead initialEntries.length
std/assembly/map.ts
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| if (initialEntries.length >= this.entriesCapacity) this.bucketsMask = initialEntries.length; | ||
| this.rehash((this.bucketsMask << 1) | 1); | ||
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| for (let i = 0; i < initialEntries.length; i++) { |
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plz cache initialEntries.length into var
std/assembly/map.ts
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| constructor() { | ||
| /* nop */ | ||
| constructor(initialEntries: MapInitialEntries<K,V> | null = null) { | ||
| if (initialEntries) { |
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Just use early return:
| if (initialEntries) { | |
| if (!initialEntries || !initialEntries.length) return; |
This will reduce one level of ident
…nd use cache initialEntries length
MapInitialEntries<K, V>= { key: K, value: V }[]• An array of { key, value } objects
• Any array typed as MapInitialEntries<K,V>
Fixes #2940