Namespace Maps

Maps associate keys with values. Several helper functions are provided for working with the standard JS Map class.

Import example

import { Maps } from 'https://unpkg.com/ixfx/dist/data.js';
Copy

Adding

• addKeepingExisting Adds items to a map only if their key does not exist already
• addObject: Adds an object, assuming each top-level property of an object is a key
• getOrGenerate: Solves a common scenario of wanting a value by a particular key, or generating it if it doesn't exist

Deleting

• deleteByValue

Finding/Iterating

• filter: Yield values that return true for predicate
• find: Finds the first value that matches a predicate, or undefined if nothing found
• hasAnyValue: Searches through all keys, returning true if any occurence of value was found
• hasKeyValue: true if value is stored under a key
• firstEntryByPredicate: Returns first entry which matches predicate
• firstEntryByValue: Returns first entry where value matches
• getClosestIntegerKey: Assuming numeric keys, find the closest to a target value
• getFromKeys: Given an iterable of keys, returns the first value where the key is present
• some: true if predicate is true for any value in map

Transforming values

• mapToArray: Applies a function to convert a map's values to an array
• mapToObjectTransform: Converts a map to a plain object, but applying a function to values
• transformMap: Like Array.map, but for Maps. Useful for generating a map as a transform of an input map.

Creating

• fromIterable: Generates a map from an interable
• fromObject
• zipKeyValue: Given an array of keys and values, combines them together into a map

To some other data

• toArray: Returns the values of the map as an array
• toObject: Coverts a Map to a plain object, useful for JSON serialising.

Etc

• sortByValue: Returns a sorted set of entries
• sortByValueProperty: Returns a sorted set of entries

See also ixfx's Collections module for custom map implementations.