Function that takes an object with optional/default properties as a parameter?

Question

I understand that, using ES6 syntax, a function can be made that takes an object as a parameter and that parameter can have a default value, like so:

functio         


        

Answer 1

You can use destructuring in parameters to provide default values:

function exampleFunction({val1 = 1, val2 = 2} = {}) {
  console.log(val1, val2);
}
exampleFunction({val1: 5});
exampleFunction();

If you want to keep the parameter as an object, you can use Object.assign:

function exampleFunction(origParams = {}) {
  const objParam = Object.assign({ val1: 1, val2: 2 }, origParams);
  console.log(objParam.val1, objParam.val2);
}
exampleFunction({val1: 5});
exampleFunction();

Answer 2

Probably not as clean as you're looking for, but you can do this instead

function exampleFunction(objParams) {
  const defParams = { val1: 1, val2: 2 };

  const finalParams = { ...defParams, ...objParams }
  // final params takes the default params and overwrites any common properties with incoming params

  // ...
}