ts-predicate/lib/esm/TypeHint.js

TypeScript predicates and assertions library

/**
* TypeHint
 *
* @class
*/
class TypeHint {
    /**
    * GetBaseType
    *
    * @description get the base type of a value.
    * @public
    * @static
    * @param {unknown} value the value
    * @return {string} string
    */
    static GetBaseType(value) {
        if (typeof value === "function") {
            // This is purely an optimization, so mutation testing is disabled.
            // Stryker disable next-line ConditionalExpression
            if (value.prototype === undefined) 
            // Stryker disable next-line BlockStatement
            {
                return "function";
            }
            const CODE = value.toString();
            if (CODE.startsWith("class ") || /^function [A-Z]/.test(CODE)) {
                return "class";
            }
            if (/^function ?\*/.test(CODE)) {
                return "generator";
            }
            return "function";
        }
        if (typeof value === "object") {
            if (value === null) {
                return "null";
            }
            if (Array.isArray(value)) {
                return "array";
            }
            return "object";
        }
        if (Number.isNaN(value)) {
            return "NaN";
        }
        return typeof value;
    }
    /**
    * GetDetailedType
    *
    * @description get the detailed type of a value.
    * @public
    * @static
    * @param {unknown} value the value
    * @return {string} string
    */
    // eslint-disable-next-line sonarjs/cognitive-complexity -- useless
    static GetDetailedType(value) {
        if (typeof value === "function") {
            if (value.name === "") {
                // This is purely an optimization, so mutation testing is disabled.
                // Stryker disable next-line ConditionalExpression
                if (value.prototype === undefined) 
                // Stryker disable next-line BlockStatement
                {
                    return "anonymous function";
                }
                // eslint-disable-next-line @typescript-eslint/no-shadow -- not shadowing anything
                const CODE = value.toString();
                if (CODE.startsWith("class ")) {
                    return "anonymous class";
                }
                if (/^function ?\*/.test(CODE)) {
                    return "anonymous generator";
                }
                return "anonymous function";
            }
            const CODE = value.toString();
            if (CODE.startsWith("class ") || /^function [A-Z]/.test(CODE)) {
                return `class ${value.name}`;
            }
            if (/^function ?\*/.test(CODE)) {
                return `generator ${value.name}`;
            }
            if (/^(?:async )?\w+\(/.test(CODE)) {
                return `method ${value.name}`;
            }
            return `function ${value.name}`;
        }
        if (typeof value === "object") {
            if (value === null) {
                return "null";
            }
            if (Array.isArray(value)) {
                return `array (${value.length.toString()} items)`;
            }
            // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- Prototype is loosely typed
            const PROTO = Object.getPrototypeOf(value);
            if (PROTO === null || PROTO === Object.prototype) {
                return "anonymous object";
            }
            if (PROTO.constructor.name === "") {
                return "object anonymous class";
            }
            return `object ${PROTO.constructor.name}`;
        }
        if (Number.isNaN(value)) {
            return "NaN";
        }
        if (typeof value === "boolean") {
            if (value) {
                return "boolean (true)";
            }
            return "boolean (false)";
        }
        if (typeof value === "number") {
            return `number (${value.toString()})`;
        }
        if (typeof value === "string") {
            return `string (${value.length.toString()} characters)`;
        }
        if (typeof value === "symbol") {
            // eslint-disable-next-line @typescript-eslint/no-magic-numbers -- useless
            return `symbol ${value.toString().slice(6)}`;
        }
        return typeof value;
    }
    /**
    * GetName
    *
    * @description Get the name of a value.
    * @public
    * @static
    * @param {unknown} value the value
    * @return {string|undefined} a string or nothing
    */
    static GetName(value) {
        if (typeof value === "function") {
            return value.name;
        }
        else if (typeof value === "object" && value !== null) {
            // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- Prototype is loosely typed
            const PROTO = Object.getPrototypeOf(value);
            if (PROTO === null) {
                return "";
            }
            return PROTO.constructor.name;
        }
        return undefined;
    }
}
export { TypeHint };