MJS is a JavaScript file that uses ES modules - the extension tells Node.js to treat it as a module with import and export rather than CommonJS. Node.js added .mjs to settle the long clash between import/export modules and the require() system it grew up with. Node.js uses the .mjs extension to force ECMAScript module mode, with .cjs forcing the older CommonJS, resolving years of ambiguity over which a .js file is. ES modules became an official part of JavaScript in 2015 and are the standard way browsers load script as modules too.

How do I open a .MJS file?

Drop a .MJS file onto Analyser at https://analyser.valjdakosta.com/ and it opens directly in your browser - no upload, no account and no software to install. Preview and inspect HTML, CSS, JavaScript, TypeScript, JSON, YAML, XML and Markdown source files, plus Windows scripts - PowerShell (PS1, PSM1, PSD1), reading their comment-based help synopsis, #Requires directives, function and parameter counts, CmdletBinding and Authenticode signing; and batch/command scripts (BAT, CMD), reading the echo state, labels, variables set and the external tools they invoke - all alongside the source.

Can I open a .MJS file online for free?

Yes. Analyser is a free online .MJS opener and viewer that runs entirely in your browser - your .MJS file never leaves your device, so there is nothing to upload and no software to install. It even works offline once installed.

.MJS file - what it is and how to open it online

Analyse a .MJS file

Home › Formats › .MJSFull

What is a .MJS file?

MJS is a JavaScript file that uses ES modules - the extension tells Node.js to treat it as a module with import and export rather than CommonJS.

Did you know: Node.js added .mjs to settle the long clash between import/export modules and the require() system it grew up with.
Node.js uses the .mjs extension to force ECMAScript module mode, with .cjs forcing the older CommonJS, resolving years of ambiguity over which a .js file is.
ES modules became an official part of JavaScript in 2015 and are the standard way browsers load script as modules too.
What Analyser shows you: Preview and inspect HTML, CSS, JavaScript, TypeScript, JSON, YAML, XML and Markdown source files, plus Windows scripts - PowerShell (PS1, PSM1, PSD1), reading their comment-based help synopsis, #Requires directives, function and parameter counts, CmdletBinding and Authenticode signing; and batch/command scripts (BAT, CMD), reading the echo state, labels, variables set and the external tools they invoke - all alongside the source.
Open a .MJS file: Drag a .MJS file onto the Analyser home page (or tap to pick one). It opens entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.
Related formats: .HTML · .CSS · .JS · .TS · .TSX · .JSX · .JSON · .YAML · .XML · .MD · .HTM · .YML · .TXT · .PS1 · .PSM1 · .PSD1 · .BAT · .CMD. See all supported file types.