String.prototype.trimStart 
An ES2019-spec-compliant String.prototype.trimStart shim. Invoke its "shim" method to shim String.prototype.trimStart if it is unavailable.
This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the spec. In an ES6 environment, it will also work properly with Symbols.
Most common usage:
var trimStart = require('string.prototype.trimstart');
assert(trimStart(' \t\na \t\n') === 'a \t\n');
if (!String.prototype.trimStart) {
trimStart.shim();
}
assert(trimStart(' \t\na \t\n') === ' \t\na \t\n'.trimStart());
Tests
Simply clone the repo, npm install, and run npm test