gobbleStringLiteral() {
		let str = '';
		const startIndex = this.index;
		const quote = this.expr.charAt(this.index++);
		let closed = false;

		while (this.index < this.expr.length) {
			let ch = this.expr.charAt(this.index++);

			if (ch === quote) {
				closed = true;
				break;
			}
			else if (ch === '\\') {
				// Check for all of the common escape codes
				ch = this.expr.charAt(this.index++);

				switch (ch) {
					case 'n': str += '\n'; break;
					case 'r': str += '\r'; break;
					case 't': str += '\t'; break;
					case 'b': str += '\b'; break;
					case 'f': str += '\f'; break;
					case 'v': str += '\x0B'; break;
					default : str += ch;
				}
			}
			else {
				str += ch;
			}
		}

		if (!closed) {
			this.throwError('Unclosed quote after "' + str + '"');
		}

		return {
			type: Jsep.LITERAL,
			value: str,
			raw: this.expr.substring(startIndex, this.index),
		};
	}
Parses a string literal, staring with single or double quotes with basic support for escape codes
e.g. `"hello world"`, `'this is\nJSEP'`
@returns {jsep.Literal}