loopStatement.js

/**
 * Description:
 *
 * If you want your code to do a lot of similar work, a loop
 * statement is a good choice. For example, if we need to
 * calculate the cumulative value from 1 to 10, we can write code like this:
 *
 * function sum1_10(){
 *  return 1+2+3+4+5+6+7+8+9+10;
 * }
 *
 * Wow~~,looks very cool! But if we need to calculate the
 * cumulative value from 1 to 100, the code becomes:
 *
 * function sum1_100(){
 *  return 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17
 *         +18+19+20+21+22+23+24+25+26+27+28+29+30+31
 *         +32+33+34+35+36+37+38+39+40+41+42+43+44+45
 *         +46+47+48+49+50+51+52+53+54+55+56+57+58+59
 *         +60+61+62+63+64+65+66+67+68+69+70+71+72+73
 *         +74+75+76+77+78+79+80+81+82+83+84+85+86+87
 *         +88+89+90+91+92+93+94+95+96+97+98+99+100;
 * }
 *
 * Do you feel a bit tired? We can use a loop statement to do it:
 *
 * function sum1_100(){
 *  var sum=0,num=1;    //Initialize two variables sum and num
 *  while (num<=100){   //Determine the expression in brackets, while true,
 *                      //run the code block one time, while false, break the loop
 *      sum=sum+num;    //Each time num will be added to the current value of sum
 *                      //It can be simplified as:  sum+=num
 *      num=num+1;      //Each time the value of num increases by 1
 *                      //It can be simplified as:  num++
 *  }
 *  return sum;         //return the final cumulative value
 * }
 *
 *
 * The do..while is a variant of while. The example
 * above can be written like this:
 *
 * function sum1_100(){
 *  var sum=0,num=1;
 *  do{
 *      sum+=num;
 *      num++;
 *  }while (num<=100)
 *  return sum;
 * }
 *
 * while judges the condition at the beginning
 * before executing its code, so if the condition is
 * false the code inside the while loop is never executed.
 * In contrast, do..while always runs once, and then starts
 * checking the condition after that.
 *
 * Finally, it is worth mentioning: Do not forget to
 * change the value of the variable (for conditional expressions),
 * otherwise it will turn into an infinite loop.
 *
 * Ok, lesson is over. Let us do a task with while.
 * Task
 * Complete function padIt, which accepts 2 parameters:
 *
 * str: a string representing the string to pad. We will
 * pad it with "*" symbols on its left side and on its right side.
 * n: a number indicating how many times to pad the string.
 *
 * Behaviour
 * You need to write a loop statement within the function
 * that loops n times. Each time through the loop it will add
 * one * to str, alternating on which side it is padded: the
 * first time will add a * to the left side of str, the second
 * time will add a * to the right side, and so on.
 *
 * Finally, return the padded string.
 * Series
 * ( ↑↑↑ Click the link above can get my newest kata list,
 * Please add it to your favorites)
 *
 * #1: create your first JS function helloWorld
 * #2: Basic data types--Number
 * #3: Basic data types--String
 * #4: Basic data types--Array
 * #5: Basic data types--Object
 * #6: Basic data types--Boolean and conditional statements if..else
 * #7: if..else and ternary operator
 * #8: Conditional statement--switch
 * #9: loop statement --while and do..while
 * #10: loop statement --for
 * #11: loop statement --break,continue
 * #12: loop statement --for..in and for..of
 * #13: Number object and its properties
 * #14: Methods of Number object--toString() and toLocaleString()
 * #15: Methods of Number object--toFixed(), toExponential() and toPrecision()
 * #16: Methods of String object--slice(), substring() and substr()
 * #17: Methods of String object--indexOf(), lastIndexOf() and search()
 * #18: Methods of String object--concat() split() and its good friend join()
 * #19: Methods of String object--toUpperCase() toLowerCase() and replace()
 * #20: Methods of String object--charAt() charCodeAt() and fromCharCode()
 * #21: Methods of String object--trim() and the string template
 * #22: Unlock new skills--Arrow function,spread operator and deconstruction
 * #23: methods of arrayObject---push(), pop(), shift() and unshift()
 * #24: methods of arrayObject---splice() and slice()
 * #25: methods of arrayObject---reverse() and sort()
 * #26: methods of arrayObject---map()
 * #27: methods of arrayObject---filter()
 * #28: methods of arrayObject---every() and some()
 * #29: methods of arrayObject---concat() and join()
 * #30: methods of arrayObject---reduce() and reduceRight()
 * #31: methods of arrayObject---isArray() indexOf() and toString()
 * #32: methods of Math---round() ceil() and floor()
 * #33: methods of Math---max() min() and abs()
 * #34: methods of Math---pow() sqrt() and cbrt()
 * #35: methods of Math---log() and its family
 * #36: methods of Math---kata author's lover:random()
 * #37: Unlock new weapon---RegExp Object
 * #38: Regular Expression--"^","$", "." and test()
 * #39: Regular Expression--"?", "*", "+" and "{}"
 * #40: Regular Expression--"|", "[]" and "()"
 * #41: Regular Expression--""
 * #42: Regular Expression--(?:), (?=) and (?!)
 *
 * Kata URL: https://www.codewars.com/kata/57216d4bcdd71175d6000560
 *
 *
 *
 * @param {*} str
 * @param {*} n
 */

function padIt(str, n) {
  // while
  return n > 1
    ? "*".repeat(Math.ceil(n / 2)) + str + "*".repeat(Math.floor(n / 2))
    : "*".repeat(Math.ceil(n / 2)) + str;
}