_.zipObject([props=[]], [values=[]])

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_.zipObject([props=[]], [values=[]])

_.zipObject类似fromPairs方法，接收两个数组参数，一个数组是属性标识，一个是相对应的属性值

参数

[props=[]] (Array): 属性标识符
[values=[]] (Array): 属性值

返回值

(Array): 返回新对象

例子

 

_.zipObject(['a', 'b'], [1, 2]);
// => { 'a': 1, 'b': 2 }

 

源代码：

import assignValue from './.internal/assignValue.js'
import baseZipObject from './.internal/baseZipObject.js'

/**
 * This method is like `fromPairs` except that it accepts two arrays,
 * one of property identifiers and one of corresponding values.
 *
 * @since 0.4.0
 * @category Array
 * @param {Array} [props=[]] The property identifiers.
 * @param {Array} [values=[]] The property values.
 * @returns {Object} Returns the new object.
 * @see unzip, unzipWith, zip, zipObjectDeep, zipWith
 * @example
 *
 * zipObject(['a', 'b'], [1, 2])
 * // => { 'a': 1, 'b': 2 }
 */
//类似fromPairs方法，接收两个数组参数，一个数组是属性标识，一个是相对应的属性值
function zipObject(props, values) {
  return baseZipObject(props || [], values || [], assignValue)
  //调用vaseZipObject处理
}

export default zipObject

baseZipObject

/**
 * This base implementation of `zipObject` which assigns values using `assignFunc`.
 *
 * @private
 * @param {Array} props The property identifiers.
 * @param {Array} values The property values.
 * @param {Function} assignFunc The function to assign values.
 * @returns {Object} Returns the new object.
 */
//zipObject的基础实现，使用assignFunc方法来分配value
function baseZipObject(props, values, assignFunc) {
  let index = -1//循环索引
  const length = props.length//key组成的数组长度
  const valsLength = values.length//value组成的数组长度
  const result = {}//结果对象

  while (++index < length) {
    const value = index < valsLength ? values[index] : undefined//value值，如果values没有元素了，就赋值为undefined
    assignFunc(result, props[index], value)//调用assignFunc向结果对象添加新键值
  }
  return result
}

export default baseZipObject

assignValue

import baseAssignValue from './baseAssignValue.js'
import eq from '../eq.js'

/** Used to check objects for own properties. */
const hasOwnProperty = Object.prototype.hasOwnProperty

/**
 * Assigns `value` to `key` of `object` if the existing value is not equivalent.
 *
 * @private
 * @param {Object} object The object to modify.
 * @param {string} key The key of the property to assign.
 * @param {*} value The value to assign.
 */
//将value分配给object上的key，如果和已存在的value的值不一样
function assignValue(object, key, value) {
  const objValue = object[key]//object上原来的key对应的值

  if (!(hasOwnProperty.call(object, key) && eq(objValue, value))) {
    //如果object没有key这个自身属性 或者objValue和value不相等
    if (value !== 0 || (1 / value) == (1 / objValue)) {
      baseAssignValue(object, key, value)
    }
  } else if (value === undefined && !(key in object)) {
    //如果object自身和原型链上都没有key这个属性，并且value是undefined
    baseAssignValue(object, key, value)
  }
}

export default assignValue

baseAssignValue

/**
 * The base implementation of `assignValue` and `assignMergeValue` without
 * value checks.
 *
 * @private
 * @param {Object} object The object to modify.
 * @param {string} key The key of the property to assign.
 * @param {*} value The value to assign.
 */
//assignValue和assignMergeValue的基础实现
function baseAssignValue(object, key, value) {
  if (key == '__proto__') {//如果key是__proto__，就用Object.defineProperty设置
    Object.defineProperty(object, key, {
      'configurable': true,
      'enumerable': true,
      'value': value,
      'writable': true
    })
  } else {//否则直接设置
    object[key] = value
  }
}

export default baseAssignValue