TypeScript Answers

How to fix the “Object literal may only specify known properties” error with TypeScript?

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To fix the "Object literal may only specify known properties" error with TypeScript, we can add dynamic keys properties into our interfaces with index signatures.

For instance, we write

interface Model {
  name: string;
  [others: string]: any;

const createModel = (x: Model) => {

createModel({ name: "hello", length: 100 });

to create the Model interface that has the required name property.

And we have

[others: string]: any;

to add an index signature that lets the interface allow any optional property other than name into our Model type object in addition to name.


createModel({ name: "hello", length: 100 });

won’t throw an error since the object that createModel is called with has name and another property.

By John Au-Yeung

Web developer specializing in React, Vue, and front end development.

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