lodash/test/dropWhile.spec.js

import { slice } from './utils';
import dropWhile from '../src/dropWhile';

describe('dropWhile', () => {
    const array = [1, 2, 3, 4];

    const objects = [
        { a: 2, b: 2 },
        { a: 1, b: 1 },
        { a: 0, b: 0 },
    ];

    it('should drop elements while `predicate` returns truthy', () => {
        const actual = dropWhile(array, (n) => n < 3);

        expect(actual).toEqual([3, 4]);
    });

    it('should provide correct `predicate` arguments', () => {
        let args;

        dropWhile(array, function () {
            args = slice.call(arguments);
        });

        expect(args).toEqual([1, 0, array]);
    });

    it('should work with `_.matches` shorthands', () => {
        expect(dropWhile(objects, { b: 2 })).toEqual(objects.slice(1));
    });

    it('should work with `_.matchesProperty` shorthands', () => {
        expect(dropWhile(objects, ['b', 2])).toEqual(objects.slice(1));
    });

    it('should work with `_.property` shorthands', () => {
        expect(dropWhile(objects, 'b')).toEqual(objects.slice(2));
    });
});