imtbl

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Immutable operations for JavaScript data structures

Shamelessly copied from Clojure’s core library

Why?

Because { ...obj, [key]: { ...obj[key], [key1]: f(obj[key][key1]) }} is stupid and sometimes you don't want Immutable.js in your code.

Random benchmark results

updateId               0.7 ms/op 1356 op/s
manual Object.assign   0.6 ms/op 1686 op/s

Installation

npm i imtbl

API

See more usage examples in tests

• get(coll, k, notFound) Returns the value mapped to k, notFound or undefined if k not present.
• getIn(coll, ks, notFound) Returns the value in a nested array or object, where ks is an array of keys. Returns undefined if the key is not present, or the notFound value if supplied.
• assoc(coll, k, v, ...) When applied to an object, returns a new object that contains the mapping of key(s) to val(s). When applied to an array, returns a new array that contains val at index.
• assocIn(coll, ks, v) Associates a value in a nested array or object, where ks is a sequence of keys and v is the new value and returns a new nested structure. If any levels do not exist, objects will be created.
• dissoc(coll, k, ...) Returns a new object, that does not contain a mapping for key(s).
• conj(coll, v, ...) Returns a new array or object with values 'added'.
• update(coll, k, f, ...args) 'Updates' a value in an array or an object, where k is a key and f is a function that will take the old value and any supplied args and return the new value, and returns a new array or object. If the key does not exist, undefined is passed as the old value.
• updateIn(coll, ks, f, ...args) 'Updates' a value in a nested array or object, where ks is an array of keys and f is a function that will take the old value and any supplied args and return the new value, and returns a new nested array or object. If any levels do not exist, objects will be created.