55 lines
1.4 KiB
JavaScript
55 lines
1.4 KiB
JavaScript
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'use strict'
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/**
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* Access nested property values at any depth with a simple expression.
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*
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* @module object-get
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* @typicalname objectGet
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* @example
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* ```js
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* const objectGet = require('object-get')
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*
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* const colour = objectGet(mammal, 'fur.appearance.colour')
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* const text = objectGet(el, 'children[2].children[1].children[1].textContent')
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* ```
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*
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* Helps avoid long logical expressions like:
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*
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* ```js
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* const colour = mammal && mammal.fur && mammal.fur.appearance && mammal.fur.appearance.colour
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* ```
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*/
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module.exports = objectGet
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/**
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* Returns the value at the given property.
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*
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* @param {object} - the input object
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* @param {string} - the property accessor expression.
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* @returns {*}
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* @alias module:object-get
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* @example
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* > objectGet({ animal: 'cow' }, 'animal')
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* 'cow'
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*
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* > objectGet({ animal: { mood: 'lazy' } }, 'animal')
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* { mood: 'lazy' }
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*
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* > objectGet({ animal: { mood: 'lazy' } }, 'animal.mood')
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* 'lazy'
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*
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* > objectGet({ animal: { mood: 'lazy' } }, 'animal.email')
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* undefined
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*/
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function objectGet (object, expression) {
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if (!(object && expression)) throw new Error('both object and expression args are required')
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return expression.trim().split('.').reduce(function (prev, curr) {
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var arr = curr.match(/(.*?)\[(.*?)\]/)
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if (arr) {
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return prev && prev[arr[1]] && prev[arr[1]][arr[2]]
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} else {
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return prev && prev[curr]
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}
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}, object)
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}
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