codeTest(一)

一. Square Every Digit

Note: The function accepts an integer and returns an integer

function squareDigits(num){
    return Number((''+num).split('').map(function(val){return val*val;}).join(''));

study: join() & split() & map()

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二.Convert strings to how they would be written by Jaden Smith.

Example:

Not Jaden-Cased: “How can mirrors be real if our eyes aren’t real”
Jaden-Cased: “How Can Mirrors Be Real If Our Eyes Aren’t Real”

String.prototype.toJadenCase = function(){
    return this.split(" ").map(function(word){
        return word.charAt(0).toUpperCase() + word.slice(1);
    }).join(" ");
}

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三.Create a function that takes an integer as an argument and returns “Even” for even numbers or “Odd” for odd numbers.

function even_or_odd(number) {
    return number % 2 ? "Odd" : "Even"
}

study:Boolean(odd):true; Boolean(even):false

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四.Who likes it?

Note: Given an array, find the int that appears an odd number of times.There will always be only one integer that appears an odd number of times.

function likes(names) {
    names = names || [];
    swith(names.length){
        case 0:return 'no one likes this';break;
        case 1:return names[0] + 'likes this';break;
        case 2:return names[0] + 'and" + names[1] + 'like this';break;
        case 3;return names[0] + ',' + names[1] + 'and' + names[2] + 'like this';break;
        default: return names[0] + ', ' + names[1] + ' and ' + (names.length - 2) + ' others like this';
  }
}

study: names = names || []; swith default

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五.Find the smallest integer in the array

class SmallestIntegerFinder {
    findSmallestInt(args) {
        return Math.min(args);
    }
}

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六.Format a string of names like ‘Bart, Lisa & Maggie’.

Given: an array containing hashes of names

Return: a string formatted as a list of names separated by commas except for the last two names, which should be separated by an ampersand.

Example:
list([ {name: ‘Bart’}, {name: ‘Lisa’}, {name: ‘Maggie’} ])
// returns ‘Bart, Lisa & Maggie’
list([ {name: ‘Bart’}, {name: ‘Lisa’} ])
// returns ‘Bart & Lisa’
list([ {name: ‘Bart’} ])
// returns ‘Bart’
list([])
// returns ”

function list(names){
    return names.reduce(function(prep, current, index, array){
        if(index === 0){
            return current.name;
        }
        else if(index === array.length-1){
            return previous + '&' + current.name;
        }
        else {
            return prev + ',' + current.name;
        }
    }, '');
}

function list(name) {
    var xs = names.map(p=>p.name)
    var x = xs.pop()
    return xs.length ? xs.join(",") + "&" + x: x||""
}