Method buildMessage

src/helpers/parser.js:46–153

(expected, found)

    }

    static buildMessage(expected, found) {
        function hex(ch) {
            return ch.codePointAt(0).toString(16).toUpperCase();
        }

        const nonPrintable = Object.prototype.hasOwnProperty.call(RegExp.prototype, "unicode")
            ? new RegExp("[\\p{C}\\p{Mn}\\p{Mc}]", "gu")
            : null;
        function unicodeEscape(s) {
            if (nonPrintable) {
                return s.replace(nonPrintable,  ch => "\\u{" + hex(ch) + "}");
            }
            return s;
        }

        function literalEscape(s) {
            return unicodeEscape(s
                .replace(/\\/g, "\\\\")
                .replace(/"/g,  "\\\"")
                .replace(/\0/g, "\\0")
                .replace(/\t/g, "\\t")
                .replace(/\n/g, "\\n")
                .replace(/\r/g, "\\r")
                .replace(/[\x00-\x0F]/g,          ch => "\\x0" + hex(ch))
                .replace(/[\x10-\x1F\x7F-\x9F]/g, ch => "\\x"  + hex(ch)));
        }

        function classEscape(s) {
            return unicodeEscape(s
                .replace(/\\/g, "\\\\")
                .replace(/\]/g, "\\]")
                .replace(/\^/g, "\\^")
                .replace(/-/g,  "\\-")
                .replace(/\0/g, "\\0")
                .replace(/\t/g, "\\t")
                .replace(/\n/g, "\\n")
                .replace(/\r/g, "\\r")
                .replace(/[\x00-\x0F]/g,          ch => "\\x0" + hex(ch))
                .replace(/[\x10-\x1F\x7F-\x9F]/g, ch => "\\x"  + hex(ch)));
        }

        const DESCRIBE_EXPECTATION_FNS = {
            literal(expectation) {
                return "\"" + literalEscape(expectation.text) + "\"";
            },

            class(expectation) {
                const escapedParts = expectation.parts.map(
                    part => (Array.isArray(part)
                        ? classEscape(part[0]) + "-" + classEscape(part[1])
                        : classEscape(part))
                );

                return "[" + (expectation.inverted ? "^" : "") + escapedParts.join("") + "]" + (expectation.unicode ? "u" : "");
            },

            any() {
                return "any character";