Convert JavaScript Object to TypeScript Online

Generate TypeScript Types from JavaScript Object Literals

JavaScript object literals are flexible: unquoted keys, single quotes, trailing commas, and comments are all valid in code but not in strict JSON. When you need TypeScript interfaces or type aliases from that sample data, this tool parses the object literal, infers structure, and emits ready-to-use TypeScript definitions in real time.

What this tool does

Paste a JavaScript object literal in the input panel. The converter normalizes it to JSON, then uses json-to-ts to generate TypeScript interfaces or a single mono type alias. Choose a root type name, toggle mono type output, and copy or download the result instantly.

When to use this instead of JSON-only converters

If your sample is already valid JSON, the JSON to TypeScript POJO Generator works well. Use this tool when your input comes from JavaScript source, browser devtools, or config files that use JS object syntax rather than strict JSON.

Common use cases

Turn API response samples from devtools into TypeScript types for frontend projects.
Generate interfaces from config objects copied from JavaScript modules.
Prototype data models before wiring up a full schema or ORM layer.
Create a single type alias when you prefer one consolidated type over multiple interfaces.

Related tools

Normalize object literals first with the JS Object to JSON converter, format TypeScript with the TypeScript Formatter, or generate JSON Schema from a JSON sample using the JSON to JSON Schema Generator.

Frequently Asked Questions

What JavaScript object syntax is supported?

The parser accepts unquoted keys, single-quoted strings, trailing commas, and comments. Standard JSON input also works and is converted before type generation.

What is the mono type alias option?

When enabled, the tool emits one consolidated TypeScript type alias instead of separate interface declarations. This is useful when you want a single exported type for the entire object tree.

How is the root type name used?

The root type name becomes the top-level interface or alias name in the generated output. Invalid characters are stripped, and names starting with a digit are prefixed automatically.

Does this support functions or undefined values?

No. Type generation works from data values only: strings, numbers, booleans, arrays, objects, and null. Functions, undefined, and symbols cannot be represented and will cause a parse error.

Is my data sent to a server?

No. Parsing and type generation run entirely in your browser. Your object literals never leave your device.

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JS Object To TypeScript