Nodejs Number Calculate set(key, value)

Method Source Code

'use strict';//from  w  w w .  j  a  v  a2  s.  c  o  m
const assert = require('assert');

// NaN space
const nan = Symbol('NaN');

// hide nan space
const define = Object.defineProperty;


// NaN space
Number.prototype[nan] = Object.create(null);

// secret setter
Number.prototype.set = function (key, value) {
  if (null == this || !isNaN(this)) { return this; }
  const space = this[nan];
  const accessor = {
    get() {
      return isNaN(this) ? space[key] : undefined;
    },

    set(value) { space[key] = isNaN(this) ? value : space[key]; }
  }

  space[key] = value;
  define(Number.prototype, key, accessor);

  return this;
};

assert('function' == typeof 4..set)

let variants = [
  (Infinity / -Infinity),
  (Number.NaN),
  ('' / ''),
  ('' / 0),
  (0 / 0),
  (NaN),
]

const key = 'key';
const value = 'value';

NaN.set(key, value);

// the following fail
4..set(key, value);
0..set(key, value);
0xff..set(key, value);

for (let variant of variants) {
  assert(value == variant[key])
}

assert(!4[key])
assert(!0[key])
assert(!0xff[key])

Related

1. rnd2()

   Number.prototype.rnd2 = function () {
     return Math.round(this.valueOf() * 100) / 100;
   

2. rotate()

   Number.prototype.rotate = Number.prototype.rotate || function () {
     return Math.floor((this / 10) + ((this % 10) * Math.pow(10, exports.digitLength(this) - 1)));
   };
   

3. safeDivideBy(x)

   Number.prototype.safeDivideBy = function(x) {
       var result = this.valueOf() / x;
       if(result === Infinity) {
           return 0;
       else {
           return result;
   

4. send(method)

   Number.prototype.send = function(method) {
     return this[method].call();
   };
   

5. separatorsseparators()

   Number.prototype.separators = function separators(){
     var string = this.toString();
     var x      = string.split('.');
     var x1     = x[0];
     var x2     = x.length > 1 ? '.' + x[1] : '';
     var regex  = /(\d+)(\d{3})/;
     while (regex.test(x1)) {
         x1 = x1.replace(regex, '$1' + ',' + '$2');
     return x1 + x2;
   };
   

6. setInCirclesetInCircle(lower, upper)

   Number.prototype.setInCircle = function setInCircle(lower, upper){
     var zahl = this;
     if (lower === upper){
       return lower;
     if (lower > upper){
       var l = lower;
       lower = upper;
       upper = l;
   ...
   

7. setInRangesetInRange(lower, upper)

   Number.prototype.setInRange = function setInRange(lower, upper){
     if (typeof lower === "undefined" || lower === null){
       lower = this;
     if (typeof upper === "undefined" || upper === null){
       upper = this;
     lower = parseFloat(lower) || 0;
     upper = parseFloat(upper) || 0;
   ...
   

8. sigFig(precision)

   'use strict'
   Number.prototype.sigFig = function(precision){
       if( !precision ) precision = 2;
       var d = Math.pow(10, precision);
       return ( parseInt( this.valueOf() * d) / d ).toFixed(precision);
   };
   

9. simEq(number, digits)

   DEFAULT_DIGIT = 5;
   Number.prototype.simEq = function(number, digits) {
     digits = digits == undefined ? DEFAULT_DIGIT : digits;
     var n1 = this.toFixed(digits);
     var n2 = number.toFixed(digits);
     if (n1 == -0)
       n1 = 0;
     if (n2 == -0)
       n2 = 0;
   ...