more codegolf

alternated-weight.js

const rowWeights = arr => {
    let a = 0;
    let b = 0;
    Object.entries(arr).forEach(([i, val]) => {
        i % 2 === 0 ? a += val : b += val;
      });
    return [a, b];
  }

  /* 
    Prompt
    
    Given an array of positive integers (the weights of the people), return a new array/tuple of two integers, 
    where the first one is the total weight of team 1, and the second one is the total weight of team 2.
  */

computed-type.js

const type = obj => Object.prototype.toString.apply(obj).replace(/\[object (.+)\]/i, "$1").toLowerCase();

dynamic-ternary-arr.js

const humanYearsCatYearsDogYears = n => n === 1 ? [1, 15, 15] : ((n) => {
    let v = 0;
    for (let i = 0; i <= n; i++) {
        i === 1 ? v += 15 : i === 2 ? v += 9 : i > 2 ? v += 4 : null;
    };
    return [n, v, v + (n - 2)];
  })(n);

/* 
  Code Golfin'
  
  Prompt
  
  "Return their respective ages now as [humanYears,catYears,dogYears]

  NOTES:

  humanYears >= 1
  humanYears are whole numbers only
  Cat Years
  15 cat years for first year
  +9 cat years for second year
  +4 cat years for each year after that
  Dog Years
  15 dog years for first year
  +9 dog years for second year
  +5 dog years for each year after that"

*/

num-begins-with.js

const validateCode = (code, matches) => matches.includes(Number((code+"")[0]));

simulated-parity-avg.js

const digitsAverage = input => {
    if (input < 10) { 
        return input; 
    }
    
    while (input > 9) {
        input = String(input); 
        let arr = [];
        for (let i = 0; i < input.length - 1; i++) {
            arr.push(Math.round((+input[i] + +input[i + 1]) / 2)); 
        }
        input = parseInt(arr.join(""));
        if (input < 10) {
            return input;
        }
    }
};

/* 
    Prompt
    
    "Given an integer, take the (mean) average of each pair of consecutive digits. 
    Repeat this process until you have a single integer, then return that integer.

    Note: if the average of two digits is not an integer, round the result up
    (e.g. the average of 8 and 9 will be 9)."

*/

strip-nth-occurrence.js

const remove = (s, target) => {
    if (s[s.length - 1] !== target) {
        return s;
    }
    let x = 0;
    for (let i in s) {
        if (s[i] == target) {
            break;
        }
        x += 1;
    }
    return s.slice(0, x) ? s.slice(0, x) : remove(s.slice(x + 1, s.length), target)
}

// removes all occurrences of target char from string if and only if the string ends in said target


const remove = str => {
    let arr = str.split("");
    for (let i = arr.length - 1; i > 0; i--) {
        if (arr[i] === "!") {
            arr.pop();
        }
        else {
            break;
        }
    }
    return arr.join("");
}

/*
    Prompt
    "Remove all exclamation marks from the end of sentence."

*/

xor.js

// xor using a ternary expression

const xor = (x, y) => x ? !y ? true : false : y ? true : false;