Day 6: The some helper

The some helper is used to find if any one or more elements in the given list, pass a specific condition.

The condition is passed in the iterator function, and it executes that function once for each element in the list.

If, for any element, the iterator function returns true, some() returns true. Otherwise, it returns false.

Usage and syntax is similar to every helper

Syntax

array.some(function(currentValue, index, arr), thisValue)

• currentValue: Required. The value of the current element
• index: Optional The array index of the current element
• arr: Optional. The array object the current element belongs to
• thisValue: Optional. A value to be passed to the function to be used as its “this” value.

Simple Example

Given a collection of games with mentioned least required RAM, buy the collection, if atleast one of the games can run in your computer (return true/false)

const games = [
    { name: "Counter Strike", ram: 8 },
    { name: "GTA 5", ram: 16 },
    { name: "Need for speed", ram: 12 },
    { name: "Road Rash", ram: 2 },
]

const myRam = 12;

// Without some helper
function canBuy1 (games, requiredRam) {
    let canBuy = false;
    for (let i=0; i<games.length; i++) {
        if (games[i].ram >= requiredRam) {
            canBuy = true;
            break;
        }
    }
    return canBuy;
}
console.log ('1. Can buy games? ', canBuy1 (games, myRam));

// With some, without arrow functions
function canBuy2 (games, requiredRam) {
    return games.some (function (game) {
        return game.ram >= requiredRam;
    });
}
console.log ('2. Can buy games? ', canBuy2 (games, myRam));

// With some, with arrow function  (one liner)
const canBuy3 = (games, requiredRam) => games.some (game => game.ram>=requiredRam);
console.log ('3. Can buy games? ', canBuy3 (games, myRam));

Another Example

Do the same question we did in every helper, but by usinig some helper

Slots of people are sent for driving license test, check whether each person in a slot is 18 years or above

Hint: (Every person > 18) is equivalent to (no person <18).

Try to apply this hint to do this problem using some helper instead of every helper

/**
 * Slots of people are sent for driving license test, 
 * check whether each person in a slot is 18 years or above.
 */

const slot1 = [
    { name: 'John', age: 16 },
    { name: 'Matt', age: 20 },
    { name: 'Dan', age: 17 },
];
const slot2 =  [
    { name: 'Amanda', age: 32 },
    { name: 'Kepler', age: 20 },
    { name: 'Stan', age: 25 },
];

const validateSlot = slot => !(slot.some (person => person.age<18));

console.log ("Slot 1: ", validateSlot (slot1));
console.log ("Slot 2: ", validateSlot (slot2));

Homework for you

Check whether a set of numbers has any element which is

1. Even
2. Odd
3. Prime
4. Negative
5. Positive
6. Perfect Square

Feel free to add more :)

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