The _.taketWhile the method is used to create a slice of an array in which elements are taken from the beginning. Also, these elements are taken until predicate returns falsely.
Syntax:
_.takeWhile(array, [predicate=_.identity])
Parameters: This method accepts two parameters as mentioned above and described below:
- array: This parameter holds the array to query.
- [predicate=_.identity]: This parameter holds the function invoked per iteration.
Return Value: This method is used to return the slice of array.
Example 1: Here, const _ = require(‘lodash’) is used to import the lodash library in the file.
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array var users = [ { 'user' : 'jupiter' , 'active' : false }, { 'user' : 'mercury' , 'active' : false }, { 'user' : 'saturn' , 'active' : true } ]; // Use of _.takeWhile() // method let gfg = _.takeWhile(users, function (o) { return !o.active; }); // Printing the output console.log(gfg); |
Output:
[{ user: 'jupiter', active: false }, {user: 'mercury', active: false}]
Example 2:
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array var users = [ { 'user' : 'jupiter' , 'active' : false }, { 'user' : 'mercury' , 'active' : false }, { 'user' : 'saturn' , 'active' : true } ]; // Use of _.takeWhile() // method // The `_.matches` iteratee shorthand. let gfg = _.takeWhile(users, { 'user' : 'jupiter' , 'active' : false }); // Printing the output console.log(gfg); |
Output:
[{ user: 'jupiter', active: false }]
Example 3:
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array var users = [ { 'user' : 'jupiter' , 'active' : false }, { 'user' : 'mercury' , 'active' : false }, { 'user' : 'saturn' , 'active' : true } ]; // Use of _.takeWhile() // method // The `_.matchesProperty` iteratee shorthand. let gfg = _.takeWhile(users, [ 'active' , false ]); // Printing the output console.log(gfg); |
Output:
[{ user: 'jupiter', active: false }, {user: 'mercury', active: false}]
Example 4:
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array var users = [ { 'user' : 'jupiter' , 'active' : false }, { 'user' : 'mercury' , 'active' : false }, { 'user' : 'saturn' , 'active' : true } ]; // Use of _.takeWhile() // method // The `_.property` iteratee shorthand. let gfg = _.takeWhile(users, 'active' ); // Printing the output console.log(gfg); |
Output:
[]
Note: This code will not work in normal JavaScript because it requires the library lodash to be installed.