Arrays

How to Check Array Conditions

Use .some() to check if any element matches, .every() for all

Quick Answer (2024 ES6+ Way)

javascript

const numbers = [1, 2, 3, 4, 5];
const hasEven = numbers.some(n => n % 2 === 0);
const allPositive = numbers.every(n => n > 0);
console.log(hasEven, allPositive); // true true

Live Example

javascript

const users = [
  { name: 'Alice', age: 25, verified: true },
  { name: 'Bob', age: 17, verified: false },
  { name: 'Charlie', age: 30, verified: true }
];

// Check if any user is underage
const hasMinor = users.some(user => user.age < 18);
console.log(`Has minor: ${hasMinor}`);

// Check if all users are verified
const allVerified = users.every(user => user.verified);
console.log(`All verified: ${allVerified}`);

Common Variations

Validation

javascript

const isValid = formFields.every(field => 
  field.value && field.value.length > 0
);

Permission Check

javascript

const hasPermission = user.roles.some(role =>
  ['admin', 'editor'].includes(role)
);

❌ Don't Do This (Outdated Way)

Avoid manual loops for existence checks

javascript

// DON'T DO THIS
var hasEven = false;
for (var i = 0; i < numbers.length; i++) {
  if (numbers[i] % 2 === 0) {
    hasEven = true;
    break;
  }
}

Browser Support

✓ Works in all modern browsers (ES5+)

#array#some#every