chai-string

var chai = require('chai');
chai.use(require('chai-string'));

var d1 = 'abcdef',
    d2 = 'abc';

d1.should.startWith.d2
expect(d1).to.startsWith(d2)
assert.startsWith(d1, d2)

assert.startsWith('abcdef', 'abc');
expect('abcdef').to.startsWith('abc');
'abcdef'.should.startWith('abc');

assert.endsWith('abcdef', 'def');
expect('abcdef').to.endsWith('def');
'abcdef'.should.endWith('def');

assert.equalIgnoreCase('abcdef', 'AbCdEf');
expect('abcdef').to.equalIgnoreCase('AbCdEf');

assert.equalIgnoreSpaces('abcdef', 'a\nb\tc\r d  ef');
expect('abcdef').to.equalIgnoreSpaces('a\nb\tc\r d  ef');

assert.containIgnoreSpaces('abcdefgh', 'a\nb\tc\r d  ef');
expect('abcdefgh').to.containIgnoreSpaces('a\nb\tc\r d  ef');

assert.containIgnoreCase('abcdefgh', 'AbcDefGH'); 
expect('abcdefgh').to.containIgnoreCase('AbcDefGH');
'abcdef'.should.containIgnoreCase('cDe');

assert.singleLine('abcdef');
expect('abcdef').to.be.singleLine();

assert.reverseOf('abcdef', 'fedcba');
expect('abcdef').to.be.reverseOf('fedcba');

assert.palindrome('abccba');
expect('abccba').to.be.palindrome();

assert.entriesCount('abcabd', 'ab', 2);
expect('abcabd').to.have.entriesCount('ab', 2);

assert.indexOf('abcabd', 'ab', 0);
expect('abcabd').to.have.indexOf('ab', 0);