Logical OR in an Array

user_7427111 0
Viewed 1718

Here is where I want to implement my OR

return bigData.country==["US"||"JP"] && (bigData.description=="iPhone 4S")

[ A || B || C || ... ] && [ X || Y || Z ||....]

As you can see above, I am returning objects, if the value of key of object bigData.country is either US or JP, AND bigData.description is either iPhone 4S, can also be more devices.

I'm able to get the desired result, by

return (bigData.country=="US"||bigData.country=="JP") && (bigData.description=="iPhone 4S")

But as I can have convenience to add and remove from an Array, I am trying to use an array. Suggestion to use something different is also welcomed.

If you want to play around with my code here is REPL

logical-operators arrays algorithm javascript
6 Answers

You can use Array.prototype.indexOf (to be != -1) like this:

return ["US", "JP"].indexOf(bigData.country) !== -1 && ["X", "Y", "Z"].indexOf(bigData.description) !== -1;

Or in ES6, you can use Array.prototype.includes like:

return ["US", "JP"].includes(bigData.country) && ["X", "Y", "Z"].includes(bigData.description);
user_98674510

With an Array:

return ['US','JP'].indexOf(bigData.country) >= 0 &&
       ['iPhone 4S'].indexOf(bigData.description) >= 0;

With an object (possibly better performance):

return {'US': true,'JP': true}[bigData.country] &&
       {'iPhone 4S': true}[bigData.description];

As pointed out by @ibrahim mahrir, the object approach doesn't always work. For example, if bigData.country=='toString'. This is because Javascript objects come with a default baggage of methods from their default Object prototype. In a real world scenario the likelihood of running afoul of this problem is negligible, but if you want to do it really really properly, there are two options:

1 - Use hasOwnProperty():

return {'US': true,'JP': true}.hasOwnProperty(bigData.country) &&
       {'iPhone 4S': true}.hasOwnProperty(bigData.description);

2 - Use an object WITHOUT a prototype. This is more verbose to set up, but also more convenient to use. You can also write a trivial method that converts a regular object to a prototype-less object.

var countries = new Object(null);
countries['US'] = true;
countries['JP'] = true;

var descriptions = new Object(null);
descriptions['iPhone 4S'] = true;

return countries[bigData.country] &&
       descriptions[bigData.description];
user_413600

You can use Array#some() method like this:

ES6:

return ['US','JP'].some(val => bigData.country === val) && ['iPhone 4S'].some(v => bigData.description === v);

ES5:

return ['US','JP'].some(function(val){return bigData.country === val}) && ['iPhone 4S'].some(function(v){return bigData.description === v});

Demo:

let bigData = {
  country: 'JP',
  description: 'iPhone 4S'
};

console.log(['US', 'JP'].some(val => bigData.country === val) && ['iPhone 4S'].some(v => bigData.description === v));

user_36696240

Use an ES6 Set (REPL):

const countriesToKeep = new Set(['GP', 'US']);

console.log(countriesToKeep.has('UK'));

console.log(countriesToKeep.has('GP'));

user_51574540

Using Array.prototype.includes is most likely what you're after:

let valid = {
  countries: ['US', 'JP'],
  description: 'iPhone 4S'
};
let dataset = [{
  country: 'US',
  description: 'iPhone 4S',
  expected: true
}, {
  country: 'JP',
  description: 'iPhone 4S',
  expected: true
}, {
  country: 'AA',
  description: 'iPhone 4S',
  expected: false
}, {
  country: 'US',
  description: 'iPhone',
  expected: false
}]

// iterate over data values
dataset.forEach(data => {
  let is_valid = valid.countries.includes(data.country) && valid.description == data.description;
  
  console.log(
    `Country:"${data.country}"`,
    `Description:"${data.description}"`,
    `Expected:${data.expected}`,
    `Got:${is_valid}`
  );
});

user_1831810

You could use an object as data structure for testing:

var countries = {
        US: true,
        JP: true
    };


return countries[bigData.country] && ...
user_14476750
Related