How do you convert numbers between different bases in JavaScript?

I would like to convert numbers between different bases, such as hexadecimal and decimal.

Example: How do you convert hexadecimal 8F to decimal?

The API

To convert to a number from a hex string:

parseInt(string, radix)

• string: Required. The string to be parsed

• radix: Optional. A number (from 2 to 36) that represents the numeral system to be used

To convert from a number to a hex string:

NumberObject.toString(radix)

• radix: Optional. Specifies the base radix you would like the number displayed as.

Example radix values:

• 2 - The number will show as a binary value
• 8 - The number will show as an octal value
• 16 - The number will show as an hexadecimal value

---

Example Usage

Integer value to hex:

var i = 10;
console.log( i.toString(16) );

Hex string to integer value:

var h = "a";
console.log( parseInt(h, 16) );

Integer value to decimal:

 var d = 16;
 console.log( d.toString(10) );

I came to this post needing to convert from base 10 to 62 and vice-versa. Whilst the solutions here are great, parseInt and toString only support base 2 to 36. So if anyone finds themselves in a similar position to me needing base 2 to 62, I've pasted my solution below.

https://gist.github.com/ryansmith94/91d7fd30710264affeb9

function convertBase(value, from_base, to_base) {
  var range = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/'.split('');
  var from_range = range.slice(0, from_base);
  var to_range = range.slice(0, to_base);
  
  var dec_value = value.split('').reverse().reduce(function (carry, digit, index) {
    if (from_range.indexOf(digit) === -1) throw new Error('Invalid digit `'+digit+'` for base '+from_base+'.');
    return carry += from_range.indexOf(digit) * (Math.pow(from_base, index));
  }, 0);
  
  var new_value = '';
  while (dec_value > 0) {
    new_value = to_range[dec_value % to_base] + new_value;
    dec_value = (dec_value - (dec_value % to_base)) / to_base;
  }
  return new_value || '0';
}

You may try the following code, which also supports arbitrary precision numbers (larger than 2^53).

function convertBase(str, fromBase, toBase) {

    const DIGITS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/";

    const add = (x, y, base) => {
        let z = [];
        const n = Math.max(x.length, y.length);
        let carry = 0;
        let i = 0;
        while (i < n || carry) {
            const xi = i < x.length ? x[i] : 0;
            const yi = i < y.length ? y[i] : 0;
            const zi = carry + xi + yi;
            z.push(zi % base);
            carry = Math.floor(zi / base);
            i++;
        }
        return z;
    }
    
    const multiplyByNumber = (num, x, base) => {
        if (num < 0) return null;
        if (num == 0) return [];

        let result = [];
        let power = x;
        while (true) {
            num & 1 && (result = add(result, power, base));
            num = num >> 1;
            if (num === 0) break;
            power = add(power, power, base);
        }

        return result;
    }

    const parseToDigitsArray = (str, base) => {
        const digits = str.split('');
        let arr = [];
        for (let i = digits.length - 1; i >= 0; i--) {
            const n = DIGITS.indexOf(digits[i])
            if (n == -1) return null;
            arr.push(n);
        }
        return arr;
    }

    const digits = parseToDigitsArray(str, fromBase);
    if (digits === null) return null;

    let outArray = [];
    let power = [1];
    for (let i = 0; i < digits.length; i++) {
        digits[i] && (outArray = add(outArray, multiplyByNumber(digits[i], power, toBase), toBase));
        power = multiplyByNumber(fromBase, power, toBase);
    }

    let out = '';
    for (let i = outArray.length - 1; i >= 0; i--)
        out += DIGITS[outArray[i]];
        
    return out;
}

Usage:

console.log(convertBase("5a2a9c826c75045be9ba8fbffc80c6f25a2a9c826c75045be9ba8fbffc80c6f2",16,64));
// Returns: 5EGD89ItghrWrGfL/O0NL9qaFO2r7k4m+CWzX/YwcrO

console.log(convertBase("5EGD89ItghrWrGfL/O0NL9qaFO2r7k4m+CWzX/YwcrO",64,16));
// Returns: 5a2a9c826c75045be9ba8fbffc80c6f25a2a9c826c75045be9ba8fbffc80c6f2

The basic code has been found here, I have a bit improved it to also support up to base 64.

The following diagram might help. Note that to convert from base 16 to base 2 you need to convert first to base 10 and then base 2.

This function generate decimal number to any base from 2 to 36.(as like javascript)

But you can Increase the base more than 36 just by adding new character in keys[] like lowercase["a","b"]

function toBase(num, radix = 10) { // only i64 numbers
  var keys = ['🤢', '😃', 2, 3, 4, 5, 6, 7, 8, 9, "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
  if (!(radix >= 2 && radix <= keys.length)) throw new RangeError("toBase() radix argument must be between 2 and " + keys.length)

  if (num < 0) var isNegative = true
  if (isNaN(num = Math.abs(+num))) return NaN

  let output = [];
  do {
    let index = num % radix;
    output.unshift(keys[index]);
    num = Math.trunc(num / radix);
  } while (num != 0);
  if (isNegative) output.unshift('-')
  return output.join("");
}

console.log(toBase("100",2)) 

Well, I made a function that could translate from base 10 to any base. (This depends on how many strings you have in the array A, if it's more than that + 10 it'll run out of symbols), and I almost cried when I found out you could to it in less than 10 characters with that...

Add a bookmark and as URL insert this... I've done it the long but personal way. At least, mine can use a base which is higher than 36. You can add more symbols yourself, but if you want, I can make it for you...

var X = prompt("Choose your number");
var Y = prompt("Choose your base");
var Z = [];
var M = -1;
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
var B = function() {
    for (i = X; 0 < i; i = Math.floor(i / Y)) { 
        if(i % Y >= 10) { 
            Z.push(A[i % Y - 10]);
        } else { 
            Z.push(i % Y);
        } 
        M = M + 1;
    } 
    for (j = M; j >= 0; j--) {
        document.write(Z[j]);
    } 
};

B(); // Call function

Specify the radix you want to use as a parameter.

NOTE: This only works to convert from bases 2-36 to decimal and little values.

parseInt(string, radix) 

parseInt("80", 10) // results in 80
parseInt("80", 16) // results in 128
// etc

About "little", parseInt("6f", 32) is fine (= 207),
but any other little bigger will be also 207, 6f1, 6f11, ...

Usually I use this function to convert from different bases.

For example, it returns "11111111" for both cases: convertBase("ff", 16, 2) or convertBase(0xFF, 16, 2)

var convertBase = function(val, base1, base2) {
    if (typeof(val) == "number") {
        return parseInt(String(val)).toString(base2);
    } else {
        return parseInt(val.toString(), base1).toString(base2)
    };
}

I've written a function to convert a JavaScript string from one base to another base, with the original base and the new base specified as parameters.

function convertFromBaseToBase(str, fromBase, toBase){
	var num = parseInt(str, fromBase);
    return num.toString(toBase);
}

alert(convertFromBaseToBase(10, 2, 10));

Using the parseInt function:

var noInBase10 = parseInt('8F',16);

Check the complete JS code to convert into different base

/**
* Convert From/To Binary/Decimal/Hexadecimal in JavaScript
* https://gist.github.com/shamshul2007/
* Copyright 2012-2015, Shamshul <[email protected]>
* Licensed under The MIT License
* http://www.opensource.org/licenses/mit-license
*/

(function(){

    var ConvertBase = function (num) {
        return {
            from : function (baseFrom) {
                return {
                    to : function (baseTo) {
                        return parseInt(num, baseFrom).toString(baseTo);
                    }
                };
            }
        };
    };
        
    // binary to decimal
    ConvertBase.bin2dec = function (num) {
        return ConvertBase(num).from(2).to(10);
    };
    
    // binary to hexadecimal
    ConvertBase.bin2hex = function (num) {
        return ConvertBase(num).from(2).to(16);
    };
    
    // decimal to binary
    ConvertBase.dec2bin = function (num) {
        return ConvertBase(num).from(10).to(2);
    };
    
    // decimal to hexadecimal
    ConvertBase.dec2hex = function (num) {
        return ConvertBase(num).from(10).to(16);
    };
    
    // hexadecimal to binary
    ConvertBase.hex2bin = function (num) {
        return ConvertBase(num).from(16).to(2);
    };
    
    // hexadecimal to decimal
    ConvertBase.hex2dec = function (num) {
        return ConvertBase(num).from(16).to(10);
    };
    //Octal to Decimal
    ConvertBase.oct2dec = function (num) {
        return ConvertBase(num).from(8).to(10);
    };
    
     //Decimal to Octal
    ConvertBase.dec2oct = function (num) {
        return ConvertBase(num).from(10).to(8);
    };
    
    this.ConvertBase = ConvertBase;
    
})(this);

/*
* Usage example:
* ConvertBase.bin2dec('1111'); // '15'
* ConvertBase.dec2hex('82'); // '52'
* ConvertBase.hex2bin('e2'); // '11100010'
* ConvertBase.dec2bin('153'); // '10011001'
* ConvertBase.hex2dec('1FE4ED63D55FA51E'); //'2298222722903156000'
* ConvertBase.oct2dec('777'); //'511'
* ConvertBase.dec2oct('551'); //'1047'
*/

This function converts a number from base 10, to an arbitrary base:

function to_base(base, num) {
    const largest_power = ~~(Math.log(num) / Math.log(base));
    const result = [];
    for (let pow = largest_power; pow >= 0; pow--) {
        const digit = ~~(num / base ** pow);
        num -= digit * base ** pow;
        result.push(digit);
    }
    return result;
}

to_base(2, 13) // [1, 1, 0, 1]
to_base(10, 458) // [4, 5, 8]
to_base(32, 1024) // [1, 0, 0]
to_base(32, 1023) // [31, 31]

which can be useful if you want to use weird bases along with weird char-set

Try the following code, optimised from Slavik Meltser's post, implements BASE n conversions with all the radix combinations between Base2 and Base256. This code accepts three sorts of arguments to define source and destination number systems:

• by number system radix (e.g. 8)
• by number system convention name (e.g. 'Bitcoin')
• by giving custom numerals as an argument (e.g. ['0123456789ABCDEF'])

You'll see that some number system numerals have been hard-coded inside the class and will be used as default when you pass the radix as an argument. (.e.g. 64) When no hard-coded numeral exists (e.g. 16), default numerals are assigned for all radixes ranging between Base2 and Base256, which becomes very clear in the self-test further below.

function BASE() {
  /**
   * BASE n converter doing all the radix combinations between Base2 and Base256
   * @param  {String}               str         input number
   * @param  {Number|String|Array}  fromBase    input number system radix (Number, e.g. 64), convention name (String, e.g. 'Bitcoin') or range (Array)
   * @param  {Number|String|Array}  toBASE      output number system radix (Number), convention name (String) or range (Array e.g. ['0123456789'])
   * @return {String}                           output number
   */
    this.convert = function (str, fromBase, toBASE)
    {
      if(typeof(fromBase)=='object') { this.fromSymbols = fromBase[0] } else this.fromSymbols = this.getsymbols(fromBase);
      if(typeof(toBASE)  =='object') { this.toSymbols = toBASE[0] } else this.toSymbols = this.getsymbols(toBASE);
      fromBase = this.fromSymbols.length; toBASE = this.toSymbols.length;

      // PARSE INPUT DIGITS ARRAY
      for(var _a = [0], str = str.split(''); str.length > 0 && _a[_a.push(this.fromSymbols.indexOf(str.pop())) - 1] >= 0;);
      var _d = _a.shift() + _a[_a.length-1]>=0 ? _a : null; if (_d === null) return null;

      // BASE CONVERSION
      for (var _n = 0,_a = [],_p = [1]; _n < _d.length; _n++) { _a = add(_a, mul(_d[_n], _p, toBASE), toBASE); _p = mul(fromBase, _p, toBASE) }

      // PARSE OUTPUT DIGITS ARRAY
      for (var _n = _a.length - 1, _o = ''; _n >= 0; _o += this.toSymbols[_a[_n--]]);
      return _o.length==0?this.toSymbols[0]:_o;
    }

    this.symbols = {
        32:function(){return this["base32hex"]},
        36:["[0-9][A-Z]"],
        45:function(){return this["qr-alnum"]},
        58:function(){return this["Bitcoin"]},
        64:["[A-Z][a-z][0-9]+/"],
        85:function(){return this["RFC 1924"]},
        91:["[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?@[]^_`{|}~\""],
        94:["[!-~]"],
    "geohash":  ["[0-9][b-h]jkmn[p-z]"],                      // base 32
    "RFC 4648": ["[A-Z][2-7]"],                               // base 32
    "base32hex": ["[0-9][A-V]"],                              // base 32
    "qr-alnum":["[0-9][A-Z] $%*+-./:"],                       // base 45
    "Bitcoin":  ["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],           // base 58
    "RFC 1924": ["[0-9][A-Z][a-z]!#$%&()*+-;<=>?@^_`{|}~"]    // base 85
    }

    this.getsymbols = function(index) {
      if(typeof(this.symbols[index])=="undefined") this.symbols[index] = index<95?this.rng(index<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-@][[-`][{-~]").substring(0,index):this.rng("[\x00-\xff]").substring(256-index,256);
      if(typeof(this.symbols[index])=="function")  this.symbols[index] = this.symbols[index]();             // process references
      if(typeof(this.symbols[index])=="object")    this.symbols[index] = this.rng(this.symbols[index][0]);  // process range_replace
      return this.symbols[index];
    }

    this.rng = function(_s) {
      var _a = _s.match(/\[.-.\]/); if(_a==null) return _s; else { _a=[_a[0].charCodeAt(1),_a[0].charCodeAt(3)];
      return this.rng(_s.replace(RegExp("\\[(\\x"+("0"+_a[0].toString(16)).slice(-2)+"-\\x"+_a[1].toString(16)+")\\]","g")
      ,String.fromCharCode(..." ".repeat(_a[1]-_a[0]+1).split("").map((_e,_i)=>_i+_a[0])) )) }
    }

    this.selftest = function() {
      var _a={}; for(var _o in this.symbols) _a[_o] = this.getsymbols(_o).length; // built-in symbols
      for(_o=2;_o<=95;_o++) _a[_o] = this.getsymbols(_o).length; _a[256]=256;     // symbol range 2-95 + 256 (96-255 is similar)
      var _s = "",_a = Object.keys(_a).sort(function(a,b){return _a[a]-_a[b]});   // sort merged list
      for(var _i in _a) {                                                         // iterate number systems
        _o = {fromBase:10, toBASE:_a[_i]}; var _r = this.convert("",10,_o.toBASE)
        _s += "\r\n\oBASE.convert(n, '"+_o.fromBase+"', '"+_o.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n"
        for(var _n=0;_n<(this.fromSymbols.length+2);_n++) {                       // iterate numbers
          _r = this.convert(String(_n),_o.fromBase,_o.toBASE)
          _s += _n+(String(_n)==this.convert(_r,_o.toBASE,_o.fromBase)?">":"?")+"["+_r+"] ";
        }
      }
      return _s
    }

    var add = function(x, y, base) {
        var _m = Math.max(x.length, y.length);
        for(var _c = _n = 0,_r = []; _n < _m || _c; _c = Math.floor(_z / base)) {
          var _z = _c + (_n < x.length ? x[_n] : 0) + (_n < y.length ? y[_n] : 0);
          var _n =  _r.push(_z % base);
        }
        return _r;
    }

    var mul = function(x, pow, base) {
        for(var _r = x < 0 ? null : []; x > 0; x = x >> 1) {
          if(x & 1) _r = add(_r, pow, base);
          pow = add(pow, pow, base);
        }
        return _r;
    }
}

Usage:

// quick test, convert from base45 to base32, using custom symbols for base85 and back to base45

var oBASE = new BASE();

var n = "THIS IS A NUMBER";                 // Base 45 code = 'qr-alnum'
console.log(n);                             // Result: 'THIS IS A NUMBER'

var n = oBASE.convert(n,"qr-alnum",32);     // Base 45 to Base 32 = 'base32hex'
console.log(n);                             // Result: '4ONI84LCTLJ1U08G1N'

var s85 = oBASE.rng("[0-9][a-z][A-Z].-:+=^!/*?&<>()[]{}@%$#"); // 32/Z85 custom symbols
var n = oBASE.convert(n,"base32hex",[s85]); // 'base2hex' to custom Base 85 
console.log(n);                             // Result: 'fnaxrZP)?5d[DG'

var n = oBASE.convert(n,[s85],45);          // Custom Base 85 to Base 45 = 'qr-alnum'
console.log(n);                             // Result: 'THIS IS A NUMBER'

function BASE(){this.convert=function(o,r,n){this.fromSymbols="object"==typeof r?r[0]:this.getsymbols(r),this.toSymbols="object"==typeof n?n[0]:this.getsymbols(n),r=this.fromSymbols.length,n=this.toSymbols.length;var i=[0];for(o=o.split("");o.length>0&&i[i.push(this.fromSymbols.indexOf(o.pop()))-1]>=0;);var h=i.shift()+i[i.length-1]>=0?i:null;if(null===h)return null;for(var e=0,l=(i=[],[1]);e<h.length;e++)i=t(i,s(h[e],l,n),n),l=s(r,l,n);e=i.length-1;for(var m="";e>=0;m+=this.toSymbols[i[e--]]);return 0==m.length?this.toSymbols[0]:m},this.symbols={32:function(){return this.base32hex},36:["[0-9][A-Z]"],45:function(){return this["qr-alnum"]},58:function(){return this.Bitcoin},64:["[A-Z][a-z][0-9]+/"],85:function(){return this["RFC 1924"]},91:['[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?@[]^_`{|}~"'],94:["[!-~]"],geohash:["[0-9][b-h]jkmn[p-z]"],"RFC 4648":["[A-Z][2-7]"],base32hex:["[0-9][A-V]"],"qr-alnum":["[0-9][A-Z] $%*+-./:"],Bitcoin:["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],"RFC 1924":["[0-9][A-Z][a-z]!#$%&()*+-;<=>?@^_`{|}~"]},this.getsymbols=function(t){return void 0===this.symbols[t]&&(this.symbols[t]=t<95?this.rng(t<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-@][[-`][{-~]").substring(0,t):this.rng("[\0-ÿ]").substring(256-t,256)),"function"==typeof this.symbols[t]&&(this.symbols[t]=this.symbols[t]()),"object"==typeof this.symbols[t]&&(this.symbols[t]=this.rng(this.symbols[t][0])),this.symbols[t]},this.rng=function(t){var s=t.match(/\[.-.\]/);return null==s?t:(s=[s[0].charCodeAt(1),s[0].charCodeAt(3)],this.rng(t.replace(RegExp("\\[(\\x"+("0"+s[0].toString(16)).slice(-2)+"-\\x"+s[1].toString(16)+")\\]","g"),String.fromCharCode(..." ".repeat(s[1]-s[0]+1).split("").map((t,o)=>o+s[0])))))},this.selftest=function(){var t={};for(var s in this.symbols)t[s]=this.getsymbols(s).length;for(s=2;s<=95;s++)t[s]=this.getsymbols(s).length;t[256]=256;var o="";t=Object.keys(t).sort(function(s,o){return t[s]-t[o]});for(var r in t){s={fromBase:10,toBASE:t[r]};var n=this.convert("",10,s.toBASE);o+="\r\noBASE.convert(n, '"+s.fromBase+"', '"+s.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n";for(var i=0;i<this.fromSymbols.length+2;i++)n=this.convert(String(i),s.fromBase,s.toBASE),o+=i+(String(i)==this.convert(n,s.toBASE,s.fromBase)?">":"?")+"["+n+"] "}return o};var t=function(t,s,o){for(var r=Math.max(t.length,s.length),n=e=0,i=[];e<r||n;n=Math.floor(h/o))var h=n+(e<t.length?t[e]:0)+(e<s.length?s[e]:0),e=i.push(h%o);return i},s=function(s,o,r){for(var n=s<0?null:[];s>0;s>>=1)1&s&&(n=t(n,o,r)),o=t(o,o,r);return n}}

Self-Test:

// quick test, convert from base45 to base32, using custom symbols for base85 and back to base45

var oBASE = new BASE();
console.log(oBASE.selftest())  
  
function BASE(){this.convert=function(o,r,n){this.fromSymbols="object"==typeof r?r[0]:this.getsymbols(r),this.toSymbols="object"==typeof n?n[0]:this.getsymbols(n),r=this.fromSymbols.length,n=this.toSymbols.length;var i=[0];for(o=o.split("");o.length>0&&i[i.push(this.fromSymbols.indexOf(o.pop()))-1]>=0;);var h=i.shift()+i[i.length-1]>=0?i:null;if(null===h)return null;for(var e=0,l=(i=[],[1]);e<h.length;e++)i=t(i,s(h[e],l,n),n),l=s(r,l,n);e=i.length-1;for(var m="";e>=0;m+=this.toSymbols[i[e--]]);return 0==m.length?this.toSymbols[0]:m},this.symbols={32:function(){return this.base32hex},36:["[0-9][A-Z]"],45:function(){return this["qr-alnum"]},58:function(){return this.Bitcoin},64:["[A-Z][a-z][0-9]+/"],85:function(){return this["RFC 1924"]},91:['[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?@[]^_`{|}~"'],94:["[!-~]"],geohash:["[0-9][b-h]jkmn[p-z]"],"RFC 4648":["[A-Z][2-7]"],base32hex:["[0-9][A-V]"],"qr-alnum":["[0-9][A-Z] $%*+-./:"],Bitcoin:["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],"RFC 1924":["[0-9][A-Z][a-z]!#$%&()*+-;<=>?@^_`{|}~"]},this.getsymbols=function(t){return void 0===this.symbols[t]&&(this.symbols[t]=t<95?this.rng(t<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-@][[-`][{-~]").substring(0,t):this.rng("[\0-ÿ]").substring(256-t,256)),"function"==typeof this.symbols[t]&&(this.symbols[t]=this.symbols[t]()),"object"==typeof this.symbols[t]&&(this.symbols[t]=this.rng(this.symbols[t][0])),this.symbols[t]},this.rng=function(t){var s=t.match(/\[.-.\]/);return null==s?t:(s=[s[0].charCodeAt(1),s[0].charCodeAt(3)],this.rng(t.replace(RegExp("\\[(\\x"+("0"+s[0].toString(16)).slice(-2)+"-\\x"+s[1].toString(16)+")\\]","g"),String.fromCharCode(..." ".repeat(s[1]-s[0]+1).split("").map((t,o)=>o+s[0])))))},this.selftest=function(){var t={};for(var s in this.symbols)t[s]=this.getsymbols(s).length;for(s=2;s<=95;s++)t[s]=this.getsymbols(s).length;t[256]=256;var o="";t=Object.keys(t).sort(function(s,o){return t[s]-t[o]});for(var r in t){s={fromBase:10,toBASE:t[r]};var n=this.convert("",10,s.toBASE);o+="\r\noBASE.convert(n, '"+s.fromBase+"', '"+s.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n";for(var i=0;i<this.fromSymbols.length+2;i++)n=this.convert(String(i),s.fromBase,s.toBASE),o+=i+(String(i)==this.convert(n,s.toBASE,s.fromBase)?">":"?")+"["+n+"] "}return o};var t=function(t,s,o){for(var r=Math.max(t.length,s.length),n=e=0,i=[];e<r||n;n=Math.floor(h/o))var h=n+(e<t.length?t[e]:0)+(e<s.length?s[e]:0),e=i.push(h%o);return i},s=function(s,o,r){for(var n=s<0?null:[];s>0;s>>=1)1&s&&(n=t(n,o,r)),o=t(o,o,r);return n}}

to convert numbers into different bases in JavaScript or typescript using the following ways.

function binary(number) {
    console.log((number >>> 0).toString(2));   //base 2 for binary
}
binary(-7);

function octal(number) {
    console.log(number.toString(8));   //base 8 for octal
}
octal(15);

function hex(number) {
    console.log(number.toString(16));   //base 16 for hex
}
hex(15);

here in the binary function, you can use number.toString(2) function, but the problem occurs when representing negative numbers. so that you can use the unsigned right shift bitwise operator (>>>) to fix this issue.

You can also convert number in hexadecimal to decimal as follows:

var a="8F";
var b=a.split("");
var result=0;var hex_multiplier=1;
for(var i=0;i<b.length;i++){
	result +=parseInt(b[i],16)*hex_multiplier;
	hex_multiplier *=16;
}
console.log(result);

where you can change a with any hexadecimal number and get the result in decimal form.

You can use JavaScript's built-in integer literals for some scenarios:

function binaryToDecimal(binaryString) {
    return Number('0b' + binaryString.replace('-', '')) * signOf(binaryString);;        
}

function octalToDecimal(octalString) {
    return Number('0o' + octalString.replace('-', '')) * signOf(octalString);
}

function hexToDecimal(hexString) {
    return Number('0x' + hexString.replace('-', '')) * signOf(hexString);
}

function signOf(n) {
  return n.trim()[0] == '-' ? -1 : 1;
}

console.log(binaryToDecimal('-0101'),
             octalToDecimal('-052171'),
               hexToDecimal('deadbeef'));

Your Own recursion method for creating base2 conversions.

As mentioned by the users above let n = 13; console.log(n.toString(2)); will result in 13 conversion from base 10 to base 2.

But in case if you want to program the same. I have written a recursive method to do the same. which just simply divide by 2 and then count remainders.

// @author Tarandeep Singh :: Created recursive converter from base 10 to base 2 
// @date : 2017-04-11
// Convert Base 10 to Base 2, We should reverse the output 
// For Example base10to2(10) = "0101" just do res = base10to2(10).split('').reverse().join();
function base10to2(val, res = '') {
  if (val >= 2) {
    res += '' + val % 2;
    return base10to2(val = Math.floor(val / 2), res);
  } else {
    res += '' + 1
    return res;
  }
}

let n = 13;

var result = base10to2(n).split('').reverse().join();
document.write(`Converting ${n} into Base2 is ${result}`);