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44 lines
904 B
44 lines
904 B
5 months ago
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'use strict';
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Object.defineProperty(exports, '__esModule', {
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value: true,
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});
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exports.keyMap = keyMap;
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/**
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* Creates a keyed JS object from an array, given a function to produce the keys
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* for each value in the array.
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*
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* This provides a convenient lookup for the array items if the key function
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* produces unique results.
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* ```ts
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* const phoneBook = [
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* { name: 'Jon', num: '555-1234' },
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* { name: 'Jenny', num: '867-5309' }
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* ]
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*
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* const entriesByName = keyMap(
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* phoneBook,
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* entry => entry.name
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* )
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*
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* // {
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* // Jon: { name: 'Jon', num: '555-1234' },
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* // Jenny: { name: 'Jenny', num: '867-5309' }
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* // }
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*
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* const jennyEntry = entriesByName['Jenny']
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*
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* // { name: 'Jenny', num: '857-6309' }
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* ```
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*/
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function keyMap(list, keyFn) {
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const result = Object.create(null);
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for (const item of list) {
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result[keyFn(item)] = item;
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}
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return result;
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}
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