Picking object properties
JavaScript
Read fire tipMapping array values with constructors
JavaScript
Some type constructors can be called as regular functions in JavaScript. We can use them when mapping over arrays to quickly transform the values in them to that type.
// values passed to a constructor are transformed to that type
[4, 8, 15].map(number => String(number)) // ⇒ ["4", "8", "15"]
["16", "23", "42"].map(string => Number(string)) // ⇒ [16, 23, 42]
[1, 1, 0].map(value => Boolean(value)) // ⇒ [true, true, false]
// we only pass the values through, so we can use this shorthand notation
[4, 8, 15].map(String) // ⇒ ["4", "8", "15"]
["16", "23", "42"].map(Number) // ⇒ [16, 23, 42]
[1, 1, 0].map(Boolean) // ⇒ [true, true, false]
More fire tips
Implicit object return in arrow functions
JavaScript
Read fire tipCatching unknown keys in lookup tables
Lookup objects can replace long if-else branches and switch statements. We can make them more resilient by checking if a value exists for a given key.
JavaScript
Read fire tip