let emptyStringArray: string [] = []; let emptyStringArray1 = new Array(); let emptyStringArray2: Array = new Array(); Steps: The first line is with inline empty array initialization. We can store the collection of key value pairs inside a map by creating a map. However, the value type of each key in the resulting object type is a union of all values for all given keys, when I want the value type to be tied to the specific key (e.g. … We will also discuss how to iterate over Map entries, Array map, clone and merge maps, merge map with an array, Convert Map Keys/Values to an Array, Weak Map, etc. Map TypeScript Map: A Complete Guide Make sense? Following are ways to convert JSOn to Map Object. However, every variable in TypeScript has a type. A Map is a standard JavaScript feature that is useful for holding key-value pairs. const projectsByMonth = data.reduce((result, project) => {. This is my function that converts record to map: type MyReturn = Map>; export const mapRecordToMap = (data: Record< Stack Overflow. javascript by Grepper on Aug 05 2019 Donate Comment . A common pattern I come across when dealing with data from REST APIs is needing to convert arrays into objects keyed on a particular property of items in the array. Typescript - How to convert Map to/from JSON with … TypeScript’s predefined types in lib.d.ts are usually very well-typed and give tons of information on how to use built-in functionality as well as providing you with extra-type safety. javascript by Grepper on Aug 05 2019 Donate Comment .