private scanStringLiteral()

in src/scanner.ts [858:960]
96 lines of code
26 McCabe index (conditional complexity)

    private scanStringLiteral(): RawToken {
        const start = this.index;
        let quote = this.source[start];
        assert((quote === '\'' || quote === '"'),
            'String literal must starts with a quote');

        ++this.index;
        let octal = false;
        let str = '';

        while (!this.eof()) {
            let ch = this.source[this.index++];

            if (ch === quote) {
                quote = '';
                break;
            } else if (ch === '\\') {
                ch = this.source[this.index++];
                if (!ch || !Character.isLineTerminator(ch.charCodeAt(0))) {
                    switch (ch) {
                        case 'u':
                            if (this.source[this.index] === '{') {
                                ++this.index;
                                str += this.scanUnicodeCodePointEscape();
                            } else {
                                const unescapedChar = this.scanHexEscape(ch);
                                if (unescapedChar === null) {
                                    this.throwUnexpectedToken();
                                }
                                str += unescapedChar;
                            }
                            break;
                        case 'x':
                            const unescaped = this.scanHexEscape(ch);
                            if (unescaped === null) {
                                this.throwUnexpectedToken(Messages.InvalidHexEscapeSequence);
                            }
                            str += unescaped;
                            break;
                        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;
                        case '8':
                        case '9':
                            str += ch;
                            this.tolerateUnexpectedToken();
                            break;

                        default:
                            if (ch && Character.isOctalDigit(ch.charCodeAt(0))) {
                                const octToDec = this.octalToDecimal(ch);

                                octal = octToDec.octal || octal;
                                str += String.fromCharCode(octToDec.code);
                            } else {
                                str += ch;
                            }
                            break;
                    }
                } else {
                    ++this.lineNumber;
                    if (ch === '\r' && this.source[this.index] === '\n') {
                        ++this.index;
                    }
                    this.lineStart = this.index;
                }
            } else if (Character.isLineTerminator(ch.charCodeAt(0))) {
                break;
            } else {
                str += ch;
            }
        }

        if (quote !== '') {
            this.index = start;
            this.throwUnexpectedToken();
        }

        return {
            type: Token.StringLiteral,
            value: str,
            octal: octal,
            lineNumber: this.lineNumber,
            lineStart: this.lineStart,
            start: start,
            end: this.index
        };
    }