_.toArray(value)

165

_.toArray(value)

_.toArray将一个值转变成数组

参数

value (*): 需要转换的值

返回值

(Array): 返回转换后的数组

例子

_.toArray({ 'a': 1, 'b': 2 });
// => [1, 2]
 
_.toArray('abc');
// => ['a', 'b', 'c']
 
_.toArray(1);
// => []
 
_.toArray(null);
// => []

源代码

import copyArray from './.internal/copyArray.js'
import getTag from './.internal/getTag.js'
import isArrayLike from './isArrayLike.js'
import isString from './isString.js'
import iteratorToArray from './.internal/iteratorToArray.js'
import mapToArray from './.internal/mapToArray.js'
import setToArray from './.internal/setToArray.js'
import stringToArray from './.internal/stringToArray.js'
import values from './values.js'

/** `Object#toString` result references. */
const mapTag = '[object Map]'
const setTag = '[object Set]'

/** Built-in value references. */
const symIterator = Symbol ? Symbol.iterator : undefined

/**
 * Converts `value` to an array.
 *
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to convert.
 * @returns {Array} Returns the converted array.
 * @example
 *
 * toArray({ 'a': 1, 'b': 2 })
 * // => [1, 2]
 *
 * toArray('abc')
 * // => ['a', 'b', 'c']
 *
 * toArray(1)
 * // => []
 *
 * toArray(null)
 * // => []
 */
//将一个值转变成数组
function toArray(value) {
  if (!value) {//如果value为假，返回空数组
    return []
  }
  if (isArrayLike(value)) {//如果value是array-like对象
    //如果是字符串，调用stringToArray转换成数组，否则是数组或者对象调用copyArray转换
    return isString(value) ? stringToArray(value) : copyArray(value)
  }
  if (symIterator && value[symIterator]) {
    //如果当前环境存在Symbol.iterator，调用iteratorToArray将遍历器转换成数组
    return iteratorToArray(value[symIterator]())
  }
  const tag = getTag(value)//获取toStringTag
  const func = tag == mapTag ? mapToArray : (tag == setTag ? setToArray : values)
  //判断是Map还是Set对象使用对应的方法处理

  return func(value)
}

export default toArray