56 lines
1.6 KiB
TypeScript
56 lines
1.6 KiB
TypeScript
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/**
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* Gets the index associated with `key` in the backing array, if it is already present.
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*/
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export let get: (strarr: SetArray, key: string) => number | undefined;
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/**
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* Puts `key` into the backing array, if it is not already present. Returns
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* the index of the `key` in the backing array.
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*/
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export let put: (strarr: SetArray, key: string) => number;
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/**
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* Pops the last added item out of the SetArray.
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*/
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export let pop: (strarr: SetArray) => void;
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/**
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* SetArray acts like a `Set` (allowing only one occurrence of a string `key`), but provides the
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* index of the `key` in the backing array.
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*
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* This is designed to allow synchronizing a second array with the contents of the backing array,
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* like how in a sourcemap `sourcesContent[i]` is the source content associated with `source[i]`,
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* and there are never duplicates.
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*/
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export class SetArray {
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private declare _indexes: { [key: string]: number | undefined };
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declare array: readonly string[];
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constructor() {
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this._indexes = { __proto__: null } as any;
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this.array = [];
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}
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static {
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get = (strarr, key) => strarr._indexes[key];
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put = (strarr, key) => {
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// The key may or may not be present. If it is present, it's a number.
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const index = get(strarr, key);
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if (index !== undefined) return index;
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const { array, _indexes: indexes } = strarr;
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return (indexes[key] = (array as string[]).push(key) - 1);
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};
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pop = (strarr) => {
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const { array, _indexes: indexes } = strarr;
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if (array.length === 0) return;
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const last = (array as string[]).pop()!;
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indexes[last] = undefined;
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};
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}
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}
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