This series uses LoDash version 4.17.4

Source code analysis does not include reference file analysis

A, source

import basePullAt from './.internal/basePullAt.js'

/**
 * Removes all elements from `array` that `predicate` returns truthy for* and returns an array of the removed elements. The predicate is invoked * with three arguments: (value, index, array). * * **Note:** Unlike `filter`, Use 'pull' * to pull elements from an array by value. * * @since 2.0.0 * @category array * @param {Array} array The array to modify. * @param {Function} predicate Thefunction invoked per iteration.
 * @returns {Array} Returns the new array of removed elements.
 * @see pull, pullAll, pullAllBy, pullAllWith, pullAt, reject, filter
 * @example
 *
 * const array = [1, 2, 3, 4]
 * const evens = remove(array, n => n % 2 == 0)
 *
 * console.log(array)
 * // => [1, 3]
 *
 * console.log(evens)
 * // => [2, 4]
 */
function remove(array, predicate) {
  const result = []
  if(! (array ! = null && array.length)) {return result
  }
  let index = -1
  const indexes = []
  const { length } = array

  while (++index < length) {
    const value = array[index]
    if (predicate(value, index, array)) {
      result.push(value)
      indexes.push(index)
    }
  }
  basePullAt(array, indexes)
  return result
}

export default remove
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Second, function function

Examples of function references:

var _= require('lodash');

//using remove.js
const array = [1, 2, 3, 4]

const evens = _.remove(array, n => n % 2 == 0)

console.log(array)
// => [1, 3]

console.log(evens)
// => [2, 4]
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As can be seen from the above example:

  • The remove function takes two parameters, array and predicate.

  • The array argument is an array, the predicate is a function.

  • The result of the remove function is an array of the elements that are true after the predicate is processed, that is, a new array of the elements that have been removed.

  • The array array consists of the remaining elements that have been removed accordingly.

Three, function working principle

  1. If array is empty, result is returned.

    if(! (array ! = null && array.length)) {return result
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} ` ` `

  1. Traversal number group;
while (++index < length) {
    const value = array[index]
    if (predicate(value, index, array)) {
      result.push(value)
      indexes.push(index)
    }
  }
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  • Place elements filtered to truth by predicate into a new array result;

  • Put the traversal index index into indexs;

  1. Removes the elements of the array corresponding to the index in indexs and returns those elements.
basePullAt(array, indexes)
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This article is from the Good Afternoon Pancake Project Web group – First look

Related links:

Daily Source Code Analysis – Lodash (chunk.js)

Daily source Code Analysis — Lodash (Slice.js)

Daily source code Analysis – Lodash (debelas.js and throttle.js)

Daily source Code Analysis -Lodash (drop.js)