format()

in core/utils.js [58:136]

• 56 lines of code
• 28 McCabe index (conditional complexity)

    format(num, format) {
        if (!format) {
            return num.toString();
        }

        const standardMatch = /^([a-zA-Z])(\d+)?(.+)?$/i.exec(format);

        if (!standardMatch) {
            return format;
        }
        
        /** @type {string} */
        const formatName = standardMatch[1];

        /** @type {number} */
        const digitNum = standardMatch[2] ? Number.parseInt(standardMatch[2]) : undefined;

        /** @type {string} */
        const extraArg = standardMatch[3];

        switch (formatName) {
            case "c":
            case "C":
                if (!extraArg) {
                    throw new Error("Number currency (C) format must include currency code, e.g. USD, CNY.");
                }

                return Intl.NumberFormat(undefined, { style: "currency", currency: extraArg, minimumFractionDigits: digitNum }).format(num);

            case "d":
            case "D":
                if (!Number.isInteger(num)) {
                    throw new Error("Decimal (D) format must be applied on an integer.");
                }

                return Intl.NumberFormat(undefined, { style: "decimal", minimumIntegerDigits: digitNum, useGrouping: false }).format(num);

            case "e":
            case "E":
                return num.toExponential(digitNum);

            case "f":
            case "F":
                return num.toFixed(digitNum >= 0 ? digitNum : 3);

            case "g":
            case "G":
                return num.toPrecision(digitNum);

            case "n":
            case "N":
                return Intl.NumberFormat(undefined, { style: "decimal", minimumFractionDigits: digitNum, useGrouping: true }).format(num);

            case "p":
            case "P":
                return Intl.NumberFormat(undefined, { style: "percent", minimumFractionDigits: digitNum >= 0 ? digitNum : 2 }).format(num);

            case "r":
            case "R":
                return num.toString(10);

            case "x":
            case "X":
                if (!Number.isInteger(num)) {
                    throw new Error("Hexadecimal (X) format must be applied on an integer.");
                }

                const numStr = num.toString(16);

                if (digitNum) {
                    return numStr.padStart(digitNum, "0");
                }

                return numStr;

            default:
                throw new Error(`Unsupported numeric format: ${format}`);
        }
    }