typescript get enum keys as array

The container object is not the same type as the enume, it is an object that contains values of the enum, so its values will be of the enum type which we can get at using T [keyof T] downvote reason: no mention that it does not work for nullable values. That said, I struggle to make variant 2 generic over. Getting an Array of all items from an Enum in Typescript + easiest +- manual with auto-completion - array, no tuple. Use the map () method to iterate over the array. Just type. That is an array of the values from the UserTags enum. Maybe it's too late, but in version 2.1 of TypeScript you can use keyof to get the type like this: Source: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-1.html#keyof-and-lookup-types. Its data is a group of constants. Adding salt pellets direct to home water tank. For Vanilla Js it should be like below: enum Colors { RED = "RED COLOR", BLUE = "BLUE COLOR", GREEN = "GREEN COLOR" } For .tsx it should be like below: Power Query Editor: Why are null Values Matching on an Inner Join? Multiple ways to Convert Enum to Array of objects in Typescript with socket.request.session.save(); // You can also send data using socket.emit () although it is not very useful socket.emit('any-key','values'); socket.on("disconnect", ()=> { //. To get only they keys or member names you can do something like this: let enums = Object. In that thread, someone just added a means to patch typescript and allow custom transformers. Enums allow a developer to define a set of named constants. This seems like a bug or an oversight. My need was to get keys of an interface as an array of strings to simplify mocha/chai scripting. First we need to convert the sizes array to a string literals array. javascript - TypeScript enum to object array The following requires you to list the keys on your own, but at least TypeScript will enforce IUserProfile and IUserProfileKeys have the exact same keys (Required was added in TypeScript 2.8): Creating an array or tuple of keys from an interface with safety compile-time checks requires a bit of creativity. PS. Any way to get the array of strings? How to get all enum names as an array in Typescript The goal is to get a list of, @CharlesCapps this can be easily solved by wrapping keyof as in. Would be great if there were a way to target specific quick-fixes, and even better if it could be done automatically on file-save, but I don't think that's possible at the time of writing. To learn more, see our tips on writing great answers. The keyof Type operator is a pretty straight forward to to so. Can we create an array of strings from a type/interface keys? With you every step of your journey. That's kind of halfway there. Use the Object.keys () method to get an array of the enum's keys. Now it's easy to enforce implementing all keys of. Sorted by: 13. Using the Object.keys(.) Using only keyof for enums wouldn't work (you'd get the keys of the enum type and not the enum constants), so you have to type keyof typeof. The example below will throw an error because 'prop4' is not a property of MyObject. TypeScript provides both numeric and string-based enums. See the TypeScript documentation for more details. createKeys does compile-time checks by merging the function parameter type with additional assertion types, that emit an error for not suitable input. for (var time in Day) { console.log(Day.time); } //OutPut AM PM Or we can directly get names of enum object using Object.keys() method. Typescript enum values as array Here's the modified code: NOTE: this assumes all ts files are located in the root of ./src and there are no subfolders, adjust accordingly. TypeScript - Enum to Array Automation and Control Engineering at CEFET/RJ, Software Developer at Radix Engineering and Software, React hooks: useSessionStorage and useLocalStorage, JavaScript: Timing the execution of a piece of code. Not that it's wrong, but to be clear here you are just "enforcing the values of the array" to be correct. Once unpublished, this post will become invisible to the public and only accessible to Saulo Dias. ETA: I was mistaken here; auto-completion has been mentioned elsewhere in the thread.). This answer is the most correct in my opinion, unfortunately there's not easier way as mentioned: Thanks for your response, i already saw and installed this custom transformer yesterday but since this uses typescript 2.4, this of no use to me as of now. let arr: A [] = Object.keys (A).map (k => A [k]) You can see it working here. Thanks for keeping DEV Community safe. so that don't have to write same method again on multiple places. TypeScript: Handbook - Enums Is there a way to define type for array with unique items in typescript? For now there is no direct support for this; and the issue is marked as "needs proposal", meaning that it's not clear how such a feature would work. As you can see, both console statements are false, because the array contains enum keys, but the includes key checks vor enum values. Interfaces don't exist at runtime. Best Five ways to iterate enum in typescript with examples? So what is the detail? (Credit goes to him.) Software Developer graduated in Automation and Control Engineering trying way too hard to become a brogrammer. How to get keys type as array from interface? Get all enum names as an array in TypeScript Use Object.keys Use Object.values Summary Get all enum names as an array in TypeScript Use Object.keys The Overflow #186: Do large language models know what theyre talking about? Lets start with defining the values we want to be the "keys" in the enum: const VALID_ENUM_VALUES = ['first', 'second', 'third'] as const; Notice the as const at the end of the statement. You could create a small function that would automatically give you a list of keys as string literals instead of a list of string (which is what Object.keys gives you) for any given object, e.g. Also easier to update at on place. Probably better off just keeping a list of keys. Relevant code: If there were missing fields, an error would be shown. However the solution looks good if someone just needs to get types out of an interface. Happy Coding! Essentially, this will assert the literal value of the array instead of widening the type to string[]. If you don't like creating a record, take a look at this alternative with Set and assertion types. const animalTypes = Object.keys(AnimalType).map((key) => ({ key , value: AnimalType [key] })); Tagged: Tips and tricks Is the DC of the Swarmkeeper ranger's Gathered Swarm feature affected by a Moon Sickle? Is there a simple way to get a list of keys/numbers from enum in rev2023.7.17.43537. In addition, they don't require a specific library (last variant uses ts-morph, which I would consider a generic compiler wrapper), emit a tuple type as opposed to an object (only first solution creates an array) or wide array type (compare to these answers) and lastly don't need classes. How to ensure an array's values the keys of a typescript interface? to enum gets key by string value in typescript by using object.key, object.value and indexOF () This is how we can enum gets by string value in typescript by using the object.key, object. index.ts enum Sizes { Small = 'S', Medium = 'M', Large = 'L', } const indexOfS = Object.values(Sizes).indexOf('S' as unknown as Sizes); const key = Object.keys(Sizes)[indexOfS]; console.log(key); Of course, you can also use the compiler API directly. As it said, a string enum is an . Instead of defining IMyTable as in interface, try defining it as a class. index.ts Create an Array with the Keys of an Interface - DEV Community TypeScript: Documentation - Keyof Type Operator For example declaring an array type of (keyof IMyTable)[] cannot catch these errors. (Source). Yes. Alternatively, you can use const assertions / as const from caller side. Typescript: String Enums, the easy way - DEV Community Two Ways to Get Enum Keys by Values in TypeScript - Webtips Find centralized, trusted content and collaborate around the technologies you use most. We can do this with const assertions as of Typescript 3.4. We're a place where coders share, stay up-to-date and grow their careers. One thing to note here is, interfaces are enforced types at compile-time, while objects are mostly run-time. The only way for me to get this to work is to remove the const declaration from the Sex enum.That is not what I want to do because I have no intention of adding additional Sex values to that enum.Thus this enum should be able to be declared as a const enum but can not be because of said aforementioned reasons. Asking for help, clarification, or responding to other answers. IMHO, we can use interfaces/types interchangeably in most of the cases. Thanks for the answer but not sure if it helps someone to use statically created Types from interface. But it's already an array, so you are now asking for an array of arrays of enum values: UserTags [] []. Working with String Enums in TypeScript | HTML Goodies There is an issue requesting a plugin support for custom transformers. Made with love and Ruby on Rails. rest of the code }) }); content_copy #javascript #typescript Typescript: Object Keys from Array | Cody Rose To get all enum values as an array, pass the enum to the Object.values () method. Finally, by using Object.values() instead of Object.keys() to create the array, you get TypeScript to recognize that FooKeys has the type ("fizz" | "buzz")[]. So, TL;DR, the following piece of code should satisfy the needs: (Here is the above code in Typescript Playground to play more). But guess what there's more. In the example below, P can be either 'x' or 'y'. The Object.keys () method returns an array of the keys of an object The Object.values () method returns an array of values or properties of an object The Object.entries () method returns Multimap of an enumeration, It is introduced in the latest Javascript language let us declare Enum in javascript or typescript Thus, all we need to do to fetch an enum's keys is pass it to the static Object.keys () method. Typescript enum constant type Enum is a new data type introduced in typescript. Defining array of enum type in Typescript ( parseInt ( x) >= 0 )); console. I wrote a simple function to convert an array of string values into an object that I'm then able to look up with obj [x] compared to array.includes (x). (Ep. Built on Forem the open source software that powers DEV and other inclusive communities. Can the people who let their animals roam on the road be punished? Though, the type computation is expensive due to combinatory complexity - performance degrades massively for more than 5-6 items. code of conduct because it is harassing, offensive or spammy. Temporary policy: Generative AI (e.g., ChatGPT) is banned. 5 Answers Sorted by: 59 Yes, it is possible to use: Object.values (MyEnum) because enum is an JS object after compilation: var MyEnum; (function (MyEnum) { MyEnum ["FOO"] = "foo"; MyEnum ["BAR"] = "bar"; }) (MyEnum || (MyEnum = {})); Share Improve this answer Follow answered May 8, 2019 at 8:27 marsibarsi 953 7 7 Stack Overflow at WeAreDevelopers World Congress in Berlin. Now we can get a type from our animals array using typeof: As others have already said, the types are not available at runtime, so you need to either generate them or write by hand. How to use the map() method with Enums in TypeScript How to type-safely remove a property from a TypeScript type, Create constant array type from an object type, How to get the property name / key name of an interface as a string in Typescript, How to check if a string is one of Interface's properties ? Hence I need to iterate over these properties in the interface and get an array out of it. Not concerned about using in the app (yet), so didn't need the ts files to be created. Lets define the type that we can use in the code, to ensure we are not using any invalid values: Instead of creating the interface using every key from enum, You can use all of your enum keys to creating a mapped type at once. Here is a really great answer that answers the problem of declaring the array of keys with type safety. As of TypeScript 2.3 (or should I say 2.4, as in 2.3 this feature contains a bug which has been fixed in typescript@2.4-dev), you can create a custom transformer to achieve what you want to do. Since enums are objects, we can use similar iterative solutions to access all values and put them in an array, such as Object.keys () function mixed with a map. Why does this journey to the moon take so long? const getKeys = <A extends object> (obj: A) => Object.keys (obj) as (keyof A) [] // ('name' | 'age') [] const keys = getKeys ( { name: 'Bob', age: 25 }) Enums Enums are one of the few features TypeScript has which is not a type-level extension of JavaScript. For further actions, you may consider blocking this person and/or reporting abuse. Actually, I have already created such a custom transformer, which enables the following. It's going to look like this: Templates let you quickly answer FAQs or store snippets for re-use. In this tutorial, you are about to learn multiple ways to convert enum to an array of objects, an array of strings, and an array of key and value pairs in typescript with examples. Here is an example of using bracket notation: enum Countries { Argentina = 'AR' as any, Armenia = 'AM' as any, Australia = 'AU' as any, Austria = 'AT' as any } console.log(Countries['AR']) The developer still needs to write them down twice, manually. How to Use enum Keys in TypeScript Interfaces and Types - Plain English ts-morph is chosen here, as it is a tad simpler wrapper alternative to the original TS compiler API. Unfortunately, the package is broken, whatever I do I am always getting, It might work well, But adding a new npm package just to get Interface keys wouldn't justify the requirement. With TS 4.1, we also can name missing keys in the error string - take a look at this Playground. Unfortunately, custom transformers are currently not so easy to use. 2 Answers Sorted by: 3 You are passing in the container object for the enum so T will be the container object. I would like a simple way to get a list of keys from an enumerator, I tried Object.keys, but it returned 6 keys, 0-5, I think it occours because when I tried foreach the enum, this returned keys and values list, is there a simple way to return only keys, I would not like to return to mount and return another list. Will i lose receiving range by attaching coaxial cable to put my antenna remotely as well as higher? Create a variable of the type and use Object.keys on it . 2. and Object.values(.) Get a list with all values from an Enum #17198 - GitHub So for your example, define/generate your class like this: You will need to make a class that implements your interface, instantiate it and then use Object.keys(yourObject) to get the properties. If you can't use a custom transformer (or prefer not to), I think the best way is what I'm about to show, which has the following advantages: The "semi-automatic" population of the array in VS Code comes from the fact that when FooKeysEnum has a red underline because it's missing properties, you can hover over it and select "Add missing properties" from the "Quick Fix" menu. (keyof IMyTable)[] | [keyof IMyTable] is a "black magic" way to force inference of a tuple instead of an array from the callee side. How to Convert a TypeScript Enum to a JavaScript Array or String + tuple +- manual with auto-completion +- more advanced, complex types. (This benefit is shared by other approaches already shown in this thread, but I don't think anyone had mentioned it yet. console.log(Day) String Enum Object entries. It doesn't know that FooKeys[0] is "fizz" and that FooKeys[1] is "buzz", but still, better than the string[] you get with Object.keys(). Making statements based on opinion; back them up with references or personal experience. Some people have suggested this, which has the benefit of being the most simple solution: However while this adds some type-safety (we cannot use non-existing properties by mistake), it is not a fully safe solution because we could miss some properties and have duplicates. If saulodias is not suspended, they can still re-publish their posts from their dashboard. 8 Answers Sorted by: 67 If you want to get your enum key by value in that case you have to rewrite your enum in following manners: But same format also might be work in older version as well. How do I make an enum of arrays in Typescript? Once suspended, saulodias will not be able to comment or publish posts until their suspension is removed. Not the answer you're looking for? I do not want to get type, I know how to do it. Can I travel between France and UK on my US passport while I wait for my French passport to be ready? Why did the subject of conversation between Gingerbread Man and Lord Farquaad suddenly change? This code will not work as the typescript syntax is not available on run-time. Problem facing when I define a new operator. Here is what you can do to flag saulodias: saulodias consistently posts content that violates DEV Community's So Object.keys and Object.values return an array with same values (regardless the type). Using enums can make it easier to document intent, or create a set of distinct cases. Variant 1 still statically enforces the resulting array to be complete. Let's look at the generator code: After we compile and run this file with tsc && node dist/mybuildstep.js, a file ./src/generated/IMyTable-keys.ts with following content is generated: + auto-generating solution + scalable for multiple properties + no helper function + tuple - extra build-step - needs familiarity with compiler API. How do I use an array of strings to be an interface's keys? filter ( x => ! 232 I have an enum defined this way: export enum GoalProgressMeasurements { Percentage = 1, Numeric_Target = 2, Completed_Tasks = 3, Average_Milestone_Progress = 4, Not_Measured = 5 } However, I'd like it to be represented as an object array/list from our API like below: typescript enum to array - IQCode methods to get the keys and values of the enum and then print it to the console. So something like ["Fitness", "Fashion"]. I'd like to have the property names of this interface in an array like this: I cannot make an object/array based on the interface IMyTable directly which should do the trick because I'd be getting the interface names of the tables dynamically. TypeScript 2022-03-27 15:55:26 Given an array, A, of integers, print N's elements in reverse order as a single line of space-separated numbers. I don't get what you mean by "initialized" @denkquer. It kind of like does to an interface the what Object.keys() does to an object. typescript - Array of Enum values: check for Enum keys with Array TypeScript TypeScript Enum to keyof Enum Array content_copy 'XXX'; // There is no auto save for session. Get keys of a Typescript interface as array of strings Find out all the different files from two different paths efficiently in Windows (with Python). let layer: { [key in keyof typeof MyEnum]: any} The keyof keyword is available since Typescript 2.1. Using Enum to populate my dropdown. What is Catholic Church position regarding alcohol? For example, in the following snippet, you can see that I created a string enum called MyStringEnum and use the Object.keys(.) Why is that so many apps today require a MacBook with an M1 chip? You can use Object.keys to get the keys of the enum and use them to get all the values. typescript - Convert array literal values to object keys - Stack Overflow In VS Code, you can also set up a keyboard shortcut in keybindings.json for executing a "Quick Fix," which makes it even quicker to trigger Add missing properties. DRY. Get interface's properties in generic way (TypeScript), typescript - how to iterate over type's properties. Your only hope is to wait for (or. Object.keys () returns an array whose elements are strings corresponding to the enumerable string-keyed property names found directly upon object. You can either use bracket notation or a combination of Object.values and Object.keys. Once unpublished, all posts by saulodias will become hidden and only accessible to themselves. The following type P is the same type as type P = "x" | "y": type Point = { x: number; y: number }; type P = keyof Point; type P = keyof Point If the type has a string or number index signature, keyof will return those types instead: Do any democracies with strong freedom of expression have laws against religious desecration? It will become hidden in your post, but will still be visible via the comment's permalink. TypeScript Enum to keyof Enum Array | thiscodeWorks Name of interface comes dynamically and then i've to determine its properties, You mean instead of an interface use a class? Well just do selected.includes ("GAS"). 2 Answers. Get all Enum Values or Names as an Array in TypeScript typescript - How to get names of enum entries? To use the map () method with enums: Use the Object.keys () method to get an array of the enum's keys. How many witnesses testimony constitutes or transcends reasonable doubt? JamieCorkhill/TypeScript-Knex-Unit-of-Work-Pattern, Deep merging of JS objects (in TypeScript), Config, Compile and Run TypeScript with Concurrently, Nodemon, & Express. - Mason That way I can use the resulting object as an allowlist/denylist that is significantly faster: function toBoolMap<A extends Array<string>> (array: A): Record<A [number], true> { return Object . How to Get Key by Value from enum String in Typescript Typescript: How to use Enum to its full potential keeping the SOLID To get the values of enum entries we can use name keys of enum object as shown below. To get all enum names as an array in Typescript, you can use the Object.keys method. The keyof operator takes an object type and produces a string or numeric literal union of its keys. You still get type support and gain the ability to get a list of keys all from a single place. Connect and share knowledge within a single location that is structured and easy to search. It's ultimately not a great solution because you have to supply values. In typescript you can use a class like an interface. Try it here. String TypeScript Enum. I downvoted because this does not solve the question as stated. An interface is something that TypeScript uses but evaporates in the JavaScript, so there's no information left to inform any "reflection" or "interspection". What is the relational antonym of 'avatar'? I use Object.keys(Color).filter(k => isNaN(Number(k))); to get my enum keys list. Implicit types resulting from above will be (you can check with VSCode or another quality IDE): and at runtime you'll be able to access the tableKeys array. Share. DEV Community 2016 - 2023. Why is copy assignment of volatile std::atomics allowed? https://github.com/kimamula/ts-transformer-keys. DEV Community A constructive and inclusive social network for software developers. Using UV5R HTs. All JavaScript knows is that there's an empty object literal. Looks like variant 1 doesn't do any work because I'll have to type out the whole keys in createKeys.