I have an array and an object and i would like a function samePrice(arr,obj) like this:

const arr = [0,1,2];
const obj = {
    0: 10,
    1: 10,
    2: 10,
    3: 12,
};

// samePrice(arr,obj) => true

const arr = [0,3];
const obj = {
    0: 10,
    1: 10,
    2: 10,
    3: 12,
};

// samePrice(arr,obj) => false

Here is my current function...

const samePrice = (arr,obj) => {
    let result = true;
  let it = obj[arr[0]];
  arr.forEach(item => {
    if (obj[item] !== it){
      result = false;
    }
  })  
  return result;
}

I am sure there is a better solution.

CodePudding user response：

Basically, what you're doing is checking that every element is the same as the first:

const samePrice = (arr,obj) => arr.every(x => obj[x] == obj[arr[0]])

const arr = [0,1,2];
const obj = {
    0: 10,
    1: 10,
    2: 10,
    3: 12,
};

console.log(samePrice(arr,obj)); // => true

const arr2 = [0,3];
const obj2 = {
    0: 10,
    1: 10,
    2: 10,
    3: 12,
};

console.log(samePrice(arr2,obj2)); // => false

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

You can use Array.every to test if something is true for all array elements. So get the object value for the first array element, then test if every element is equal to that.

function samePrice(items, prices) {
  if (items.length == 0) {
    return true;
  }
  let price = prices[items[0]];
  return items.every(item => prices[item] == price);
}

const arr1 = [0, 1, 2];
const obj1 = {
  0: 10,
  1: 10,
  2: 10,
  3: 12,
};

console.log(samePrice(arr1, obj1));

const arr2 = [0, 3];
const obj2 = {
  0: 10,
  1: 10,
  2: 10,
  3: 12,
};

console.log(samePrice(arr2, obj2));

<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

I came up with this:

function samePrice(arr, obj) {
  if(arr.length < 1)
    return false;
  i = 1;
  while(i < arr.length) {
    if(obj[arr[i]]!=obj[arr[i-1]])
      return false;
    i  ;
  };
  return true;
}

var arr = [0,1,2];
var obj = {
    0: 10,
    1: 10,
    2: 10,
    3: 12,
};

console.log(samePrice(arr, obj));

var arr = [0,3];
var obj = {
    0: 10,
    1: 10,
    2: 10,
    3: 12,
};

console.log(samePrice(arr, obj));

<iframe name="sif3" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

You could separate the first items areference proce and check the rest of the array against it.

const
    samePrice = ([ref, ...a], prices) => a.every(k => prices[ref] === prices[k]);

console.log(samePrice([0, 1, 2], { 0: 10, 1: 10, 2: 10, 3: 12 })); //  true
console.log(samePrice([0, 3], { 0: 10, 1: 10, 2: 10, 3: 12 })); //    false

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