JAVASCRIPT cmp.js

import { DataError } from "./errors.js";
import valueToKey from "./valueToKey.js";
const getType = x => {
  if (typeof x === "number") {
    return "Number";
  }
  if (Object.prototype.toString.call(x) === "[object Date]") {
    return "Date";
  }
  if (Array.isArray(x)) {
    return "Array";
  }
  if (typeof x === "string") {
    return "String";
  }
  if (x instanceof ArrayBuffer) {
    return "Binary";
  }
  throw new DataError();
};

// https://w3c.github.io/IndexedDB/#compare-two-keys
const cmp = (first, second) => {
  if (second === undefined) {
    throw new TypeError();
  }
  first = valueToKey(first);
  second = valueToKey(second);
  const t1 = getType(first);
  const t2 = getType(second);
  if (t1 !== t2) {
    if (t1 === "Array") {
      return 1;
    }
    if (t1 === "Binary" && (t2 === "String" || t2 === "Date" || t2 === "Number")) {
      return 1;
    }
    if (t1 === "String" && (t2 === "Date" || t2 === "Number")) {
      return 1;
    }
    if (t1 === "Date" && t2 === "Number") {
      return 1;
    }
    return -1;
  }
  if (t1 === "Binary") {
    first = new Uint8Array(first);
    second = new Uint8Array(second);
  }
  if (t1 === "Array" || t1 === "Binary") {
    const length = Math.min(first.length, second.length);
    for (let i = 0; i < length; i++) {
      const result = cmp(first[i], second[i]);
      if (result !== 0) {
        return result;
      }
    }
    if (first.length > second.length) {
      return 1;
    }
    if (first.length < second.length) {
      return -1;
    }
    return 0;
  }
  if (t1 === "Date") {
    if (first.getTime() === second.getTime()) {
      return 0;
    }
  } else {
    if (first === second) {
      return 0;
    }
  }
  return first > second ? 1 : -1;
};
export default cmp;