lodash/test/trim-methods.spec.ts

import assert from 'node:assert';
import lodashStable from 'lodash';
import { _, whitespace } from './utils';

describe('trim methods', () => {
    lodashStable.each(['trim', 'trimStart', 'trimEnd'], (methodName, index) => {
        let func = _[methodName],
            parts = [];

        if (index != 2) {
            parts.push('leading');
        }
        if (index != 1) {
            parts.push('trailing');
        }
        parts = parts.join(' and ');

        it(`\`_.${methodName}\` should remove ${parts} whitespace`, () => {
            const string = `${whitespace}a b c${whitespace}`,
                expected = `${index === 2 ? whitespace : ''}a b c${index === 1 ? whitespace : ''}`;

            assert.strictEqual(func(string), expected);
        });

        it(`\`_.${methodName}\` should coerce \`string\` to a string`, () => {
            const object = { toString: lodashStable.constant(`${whitespace}a b c${whitespace}`) },
                expected = `${index === 2 ? whitespace : ''}a b c${index === 1 ? whitespace : ''}`;

            assert.strictEqual(func(object), expected);
        });

        it(`\`_.${methodName}\` should remove ${parts} \`chars\``, () => {
            const string = '-_-a-b-c-_-',
                expected = `${index === 2 ? '-_-' : ''}a-b-c${index === 1 ? '-_-' : ''}`;

            assert.strictEqual(func(string, '_-'), expected);
        });

        it(`\`_.${methodName}\` should coerce \`chars\` to a string`, () => {
            const object = { toString: lodashStable.constant('_-') },
                string = '-_-a-b-c-_-',
                expected = `${index === 2 ? '-_-' : ''}a-b-c${index === 1 ? '-_-' : ''}`;

            assert.strictEqual(func(string, object), expected);
        });

        it(`\`_.${methodName}\` should return an empty string for empty values and \`chars\``, () => {
            lodashStable.each([null, '_-'], (chars) => {
                assert.strictEqual(func(null, chars), '');
                assert.strictEqual(func(undefined, chars), '');
                assert.strictEqual(func('', chars), '');
            });
        });

        it(`\`_.${methodName}\` should work with \`undefined\` or empty string values for \`chars\``, () => {
            const string = `${whitespace}a b c${whitespace}`,
                expected = `${index === 2 ? whitespace : ''}a b c${index === 1 ? whitespace : ''}`;

            assert.strictEqual(func(string, undefined), expected);
            assert.strictEqual(func(string, ''), string);
        });

        it(`\`_.${methodName}\` should work as an iteratee for methods like \`_.map\``, () => {
            const string = Object(`${whitespace}a b c${whitespace}`),
                trimmed = `${index === 2 ? whitespace : ''}a b c${index === 1 ? whitespace : ''}`,
                actual = lodashStable.map([string, string, string], func);

            assert.deepStrictEqual(actual, [trimmed, trimmed, trimmed]);
        });

        it(`\`_.${methodName}\` should return an unwrapped value when implicitly chaining`, () => {
            const string = `${whitespace}a b c${whitespace}`,
                expected = `${index === 2 ? whitespace : ''}a b c${index === 1 ? whitespace : ''}`;

            assert.strictEqual(_(string)[methodName](), expected);
        });

        it(`\`_.${methodName}\` should return a wrapped value when explicitly chaining`, () => {
            const string = `${whitespace}a b c${whitespace}`;
            assert.ok(_(string).chain()[methodName]() instanceof _);
        });
    });
});