@nerdware/ddb-single-table/dist/esm/utils/isType.js

A schema-based DynamoDB modeling tool, high-level API, and type-generator built to supercharge single-table designs!⚡

import { isString, isBoolean, isBuffer, isDate, isArray, isPlainObject, } from "@nerdware/ts-type-safety-utils";
/**
 * `number` type guard function
 *
 * ### DynamoDB Numbers
 *
 * - Can be positive, negative, or zero.
 * - Can have up to 38 digits of precision (JS only supports up to 16 digits of precision).
 * - Has a positive range of 1E-130 to 9.9999999999999999999999999999999999999E+125
 * - Has a negative range of -9.9999999999999999999999999999999999999E+125 to -1E-130
 * - Leading and trailing zeroes are trimmed.
 */
export const isNumber = (value) => {
    // isFinite returns false for NaN, Infinity, -Infinity
    return typeof value === "number" && Number.isFinite(value);
};
/**
 * Type guard function for `type: "tuple"`
 *
 * > **Note:** This function does not check the types of values _within_ the provided tuple — that
 *   is accomplished by the `typeChecking` IO-Action which is applied recursively to nested values
 *   via `recursivelyApplyIOAction`.
 */
export const isTuple = (value, nestedSchema) => {
    return isArray(value) && isArray(nestedSchema) && value.length === nestedSchema.length;
};
/** Type guard function for `type: "enum"` */
export const isEnumMember = (value, allowedValues) => {
    return isString(value) && isArray(allowedValues) && allowedValues.includes(value);
};
/**
 * Type guard/safety functions for each of the supported schema attribute `type` values.
 */
export const isType = Object.freeze({
    /** Type guard function for `type: "string"` */
    string: isString,
    /** Type guard function for `type: "number"` */
    number: isNumber,
    /** Type guard function for `type: "boolean"` */
    boolean: isBoolean,
    /** Type guard function for `type: "Buffer"` */
    Buffer: isBuffer,
    /** Type guard function for `type: "Date"` */
    Date: isDate,
    /** Type guard function for `type: "array"` */
    array: isArray,
    /** Type guard function for `type: "map"` */
    map: isPlainObject,
    /** Type guard function for `type: "tuple"` */
    tuple: isTuple,
    /** Type guard function for `type: "enum"` */
    enum: isEnumMember,
});