Ramda: Suggestion: Null-safe `get`

[cjohansen]

Lodash has get (similar to Clojure's get-in), to grab for nested properties in a null-safe manner:

const obj = {};
get(obj, ['some', 'nested', 'property']) //=> null

As opposed to:

const obj = {};
obj.some.nested.property //=> Boom!

Lodash also supports a default value, which is quite handy. I guess I want a shorthand for this:

defaultTo(42, prop('nested', prop('something', obj)))

I guess it might have to be two functions as variadic functions and auto-currying doesn't mix to well.

const get = curry((path, target) => {
  return path.reduce((res, p) => res && res[p], target);
});

const getWithDefault = curry((path, defaultVal, target) => {
  return path.reduce((res, p) => {
    const val = res && res[p];
    return val === null || val === undefined || typeof val === 'number' && isNaN(val) ? defaultVal : val;
  }, target);
});

[asaf-romano]

See path, pathOr and propOr.

[CrossEye]

I think path already does what you want. Ramda also already has propOr, and pathOr for default values. You might also look at lensPath which creates a lens for a particular path with which you can then view, set, or adjust the value with over.

[buzzdecafe]

... although the real killer feature of lenses is that they compose

[cjohansen]

Cool, thanks!