ES2019 introduces String.prototype.trimStart() and String.prototype.trimEnd():

const string = '  hello world  ';
string.trimStart();
// → 'hello world  '
string.trimEnd();
// → '  hello world'
string.trim(); // ES5
// → 'hello world'

This functionality was previously available through the non-standard trimLeft() and trimRight() methods, which remain as aliases of the new methods for backward compatibility.

const string = '  hello world  ';
string.trimStart();
// → 'hello world  '
string.trimLeft();
// → 'hello world  '
string.trimEnd();
// → '  hello world'
string.trimRight();
// → '  hello world'
string.trim(); // ES5
// → 'hello world'

String.prototype.trim{Start,End} support #

• Chrome: supported since version 66
• Firefox: supported since version 61
• Safari: supported since version 12
• Node.js: supported since version 8
• Babel: supported