Lodash _.isEqualWith() Method

Lodash is a JavaScript library that works on the top of underscore.js. Lodash helps in working with arrays, strings, objects, numbers, etc.

The _.isEqualWith() method of Lang in lodash is similar to _.isEqual() method and the only difference is that it accepts customizer which is called in order to compare values. Moreover, if the customizer used here returns undefined then the comparisons are dealt by the method instead. 

Note: The customizer used here can be called with up to six arguments namely objValue, othValue, index|key, object, other, and stack.

Syntax:

_.isEqualWith(value, other, [customizer])

Parameters: This method accepts three parameters as mentioned above and described below:

• value: It is the value to be compared.
• other: It is the other value to be compared.
• customizer: It is the function which is used to customize comparisons.

Return Value: This method returns true if the stated values are equivalent otherwise it returns false.

Example 1:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Defining a function portal
function portal(val) {
  return /^G(?:fG|eeksforGeeks)$/.test(val);
}

// Defining customizer to compare values
function customizer(objectValue, otherValue) {
  if (portal(objectValue) && portal(otherValue)) {
    return true;
  }
}

// Initializing values
var val = ['GeeksforGeeks', 'CS-portal'];
var otherval = ['GfG', 'CS-portal'];

// Calling isEqualWith() method with all
// its parameter
let result = _.isEqualWith(val, otherval, customizer);

// Displays output
console.log(result);

Output:

true

Example 2:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Defining a function portal
function portal(val) {
  return /^G(?:fG|eeksforGeeks)$/.test(val);
}

// Defining customizer to compare values
function customizer(objectValue, otherValue) {
  if (portal(objectValue) && portal(otherValue)) {
    return true;
  }
}

// Initializing values
var val = ['GeeksforGeeks', 'CS-portal'];
var otherval = ['GfG', 'portal'];

// Calling isEqualWith() method with all
// its parameter
let result = _.isEqualWith(val, otherval, customizer);

// Displays output
console.log(result);

Output:

false

Example 3:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Defining a function gfg
function gfg(val) {
  return val;
}

// Defining customizer
function intg(x, y) {
 if (gfg(x) === gfg(y)){
  return true;
   }
}

// Calling isEqualWith() method with all
// its parameter
let result = _.isEqualWith('gf', 'gfg', intg);

// Displays output
console.log(result);

Output:

false

Reference: https://lodash.com/docs/4.17.15#isEqualWith