5 Practical JavaScript Tricks to Write Cleaner Conditional Logic

1. Use Array.includes for multiple matching criteria

Replace long || chains with Array.includes to test if a value is in a list.

function test(fruit) {
  if (['apple', 'strawberry', 'cherry', 'cranberries'].includes(fruit)) {
    console.log('red');
  }
}

2. Reduce nesting with early return

Validate inputs early and exit the function when a condition fails, flattening control flow.

function test(fruit, quantity) {
  if (!fruit) throw new Error('No fruit!');
  if (!['apple', 'strawberry', 'cherry', 'cranberries'].includes(fruit)) return;
  if (quantity > 10) console.log('big quantity');
  else console.log('red');
}

3. Use default parameters and destructuring

Assign default values directly in the function signature and destructure objects to avoid repetitive null checks.

// default parameter
function test(fruit, quantity = 1) {
  if (!fruit) return;
  console.log(`We have $${quantity} ${fruit}!`);
}

// destructuring with default empty object
function test({ name } = {}) {
  console.log(name || 'unknown');
}

4. Replace switch with object literals or Map

Use an object literal or a Map for key‑to‑value lookups instead of a switch statement.

// object literal lookup
const fruitColor = {
  red: ['apple', 'strawberry'],
  yellow: ['banana', 'pineapple'],
  purple: ['grape', 'plum']
};
function getFruitsByColor(color) {
  return fruitColor[color] || [];
}

// Map version
const fruitMap = new Map();
fruitMap.set('red', ['apple', 'strawberry']);
fruitMap.set('yellow', ['banana', 'pineapple']);
fruitMap.set('purple', ['grape', 'plum']);
function getFruitsByColorMap(color) {
  return fruitMap.get(color) || [];
}

5. Use Array.every and Array.some for collective checks

Use every to verify that all items satisfy a condition and some to verify that at least one item satisfies it.

const fruits = [
  { name: 'apple', color: 'red' },
  { name: 'banana', color: 'yellow' },
  { name: 'grape', color: 'purple' }
];
const allRed = fruits.every(f => f.color === 'red'); // false
const anyRed = fruits.some(f => f.color === 'red'); // true