Object Behaviors

Object with integer Keys are automatically sorted ascending

String keys are not sorted automatically

const integerKeyObject = {
  100: "a", 
  2: "b", 
  7: "c"
};

Object.keys(integerKeyObject); // ["2", "7", "100"] 

const stringKeyObject = {
  "c": "somestring",
  "a": 42,
  "b": false
};

Object.keys(stringKeyObject); // ["c", "a", "b"] 

Object Strategies

Cleanup guard clauses with lookup

// Guard Clauses
function logicalCalc(array, operation) { 
  let result = array[0];

  for(let i = 1; i < array.length; i++) { 
    if(operation === 'AND') {
      result = result && array[i];
    }
    if(operation === 'OR') {
      result = result || array[i];
    }
    if(operation === 'XOR') {
      result = result !== array[i];
    }
  }
  return result;
}

logicalCalc([false, true, 3], 'AND');

// Object Key Lookup
const operations = {
  AND: (a, b) => a && b, 
  OR: (a, b) => a || b, 
  XOR: (a, b) => a !== b, 
};

const logicalCalc = (array, options) => array.reduce(operations[options]);

logicalCalc([1,2,3], 'AND');

Methods

.map()

Map can be used to get all specified keys of objects

const items = [
	{name: "Bike", price: 100},
	{name: "Dish", price: 50}
];
const itemNames = items.map( (item)=>{
	return item.name;
});

console.log(itemNames); // ["Bike", "Dish"]