dlv(obj, keypath) 
Safely get a dot-notated path within a nested object, with ability to return a default if the full key path does not exist or the value is undefined
Why?
Smallest possible implementation: only 120 bytes.
You could write this yourself, but then you'd have to write tests.
Supports ES Modules, CommonJS and globals.
Installation
npm install --save dlv
Usage
delve(object, keypath, [default])
import delve from 'dlv';
let obj = {
a: {
b: {
c: 1,
d: undefined,
e: null
}
}
};
//use string dot notation for keys
delve(obj, 'a.b.c') === 1;
//or use an array key
delve(obj, ['a', 'b', 'c']) === 1;
delve(obj, 'a.b') === obj.a.b;
//returns undefined if the full key path does not exist and no default is specified
delve(obj, 'a.b.f') === undefined;
//optional third parameter for default if the full key in path is missing
delve(obj, 'a.b.f', 'foo') === 'foo';
//or if the key exists but the value is undefined
delve(obj, 'a.b.d', 'foo') === 'foo';
//Non-truthy defined values are still returned if they exist at the full keypath
delve(obj, 'a.b.e', 'foo') === null;
//undefined obj or key returns undefined, unless a default is supplied
delve(undefined, 'a.b.c') === undefined;
delve(undefined, 'a.b.c', 'foo') === 'foo';
delve(obj, undefined, 'foo') === 'foo';
Setter Counterparts
- dset by @lukeed is the spiritual "set" counterpart of
dlvand very fast. - bury by @kalmbach does the opposite of
dlvand is implemented in a very similar manner.