algorithm: add IntToBase algo and a test for it (TheAlgorithms#1258)

Author: Saimon398

Maths/IntToBase.js

@@ -0,0 +1,40 @@
+/**
+ * @function intToBase
+ * @description Convert a number from decimal system to another (till decimal)
+ * @param{Number} number Number to be converted
+ * @param{Number} base Base of new number system
+ * @returns{String} Converted Number
+ * @see [HornerMethod](https://en.wikipedia.org/wiki/Horner%27s_method)
+ * @example
+ * const num1 = 125 // Needs to be converted to the binary number system
+ * gornerScheme(num, 2); // ===> 1111101
+ * @example
+ * const num2 = 125 // Needs to be converted to the octal number system
+ * gornerScheme(num, 8); // ===> 175
+ */
+constintToBase=(number,base)=>{
+if(typeofnumber!=='number'||typeofbase!=='number'){
+thrownewError('Input data must be numbers')
+}
+// Zero in any number system is zero
+if(number===0){
+return'0'
+}
+letabsoluteValue=Math.abs(number)
+letconvertedNumber=''
+while(absoluteValue>0){
+// Every iteration last digit is taken away
+// and added to the previous one
+constlastDigit=absoluteValue%base
+convertedNumber=lastDigit+convertedNumber
+absoluteValue=Math.trunc(absoluteValue/base)
+}
+// Result is whether negative or positive,
+// depending on the original value
+if(number<0){
+convertedNumber='-'+convertedNumber
+}
+returnconvertedNumber
+}
+
+export{intToBase}

Maths/test/IntToBase.test.js

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+import{intToBase}from'../intToBase'
+
+describe('Int to Base',()=>{
+test('Conversion to the binary system',()=>{
+expect(intToBase(210,2)).toEqual('11010010')
+expect(intToBase(-210,2)).toEqual('-11010010')
+})
+test('Conversion to the system with base 5',()=>{
+expect(intToBase(210,5)).toEqual('1320')
+expect(intToBase(-210,5)).toEqual('-1320')
+})
+test('Conversion to the octal system',()=>{
+expect(intToBase(210,8)).toEqual('322')
+expect(intToBase(-210,8)).toEqual('-322')
+})
+test('Output is 0',()=>{
+expect(intToBase(0,8)).toEqual('0')
+expect(intToBase(0,8)).toEqual('0')
+})
+test('Throwing an exception',()=>{
+expect(()=>intToBase('string',2)).toThrow()
+expect(()=>intToBase(10,'base')).toThrow()
+expect(()=>intToBase(true,false)).toThrow()
+})
+})