The Lodash _.differenceBy() method is used to remove the values from the original array by iterating over each element in the array by using the Iterate function. It is almost the same as _.difference() function.
Syntax
lodash.differenceBy(array, [values], [iterate=_.identity])Parameters
This function accepts three parameters as mentioned above and described below
- array: This is the array from which the values are to be removed.
- values: It is the Array of values that is to be removed from the original array.
- Iterate: This is the function that iterate over each element.
Note: If the iterate function is not given then _.differenceBy() function act as _.difference() function.
Return Value
- This function returns an array.
Example 1: In this example, we use the lodash library to subtract one array (val) from another (array1).
// Requiring the lodash library
const _ = require("lodash");
// Original array
let array1 = [1, 2, 3, 4.2]
// Array to be subtracted
let val = [2, 3, 3, 5]
// New Array after _.differenceBy()
// method where Math.double is the
// comparable function
let newArray = _.differenceBy(
array1, val, Math.double);
// Printing the original array
console.log("Before : ", array1);
// Printing the output
console.log("After : ", newArray);
Output:
Example 2: In this example, we use lodash library to find differences between arrays, with and without a custom comparator function.
// Requiring the lodash library
const _ = require("lodash");
// Original array
let array1 = [1, 2, 3, 4.2]
// Value array to be subtracted
let val = [2, 3, 4, 5]
// new Array after _.differenceBy()
// method where Math.double is the
// comparable function
let newArray1 = _.differenceBy(
array1, val, Math.floor);
// New Array after _.differenceBy function
// where no comparable function is given
let newArray2 = _.differenceBy(array1, val);
// Printing the original array
console.log("Before : ", array1);
// printing the output
console.log("When compare funct is given: ",
newArray1);
// Printing the output
console.log("When compare funct is not given: ",
newArray2);
Output:
