Avoid using delete operator

The use of the delete operator has performance negative effects for the V8 hidden classes pattern. In general it’s recommended do not use it.

Alternatively, to remove object own enumerable properties, we could create a new object copy without those properties (example using lodash):

_.omit(o, 'prop', 'prop2')

Or even define the property value to null or undefined (which is implicitly ignored when serializing to JSON):

o.prop = undefined

[justinmchase]

You can also delete with destructuring:

const obj1 = { a: 1, b: 2 }
const { a, ...obj2 } = obj1
console.log(obj2) // { b: 2 }

[robertrossmann]

I am not against code optimisations, but I always believed there should be a balance between code readability and clarity and actual performance gains when deciding whether or not an optimisation should be done to code.

In this particular case, we call delete about 5 times (did not count properly) before each API request which usually takes about 200-600ms to complete. I am skeptic on the performance boost gained by ditching delete in favour of setting a property to undefined. In practice, we are probably talking about gains of 1ms/request at most.😃

That being said, lib/apirequest.js sure could use some rewrite! (that’s where most delete calls are)