ES Modules were introduced in ES2015. The import and export keywords by default are only applicable to JavaScript code. But there is a new proposal to allow it to be used for JSON modules in JavaScript.
It is convenient to keep some configuration inside a JSON file and import that. And this was possible using the commonjs module format. The proposal will allow us to do import JSON Modules in an ES module.
Let us assume we have a configuration file called configuration.js. The following will give an error by default:
import config from './configuration.json';
JavaScriptNode.js will throw the following error:
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".json"
JavaScriptThe proposal now allows us to import JSON modules using an import assertion.
import jsonObject from "./file.json" assert { type: "json" };
JavaScriptassert { type: “json” } is what is defined as an import assertion that specifies the type of the module and how it should be parsed and imported as.
The jsonObject variable will contain the JavaScript object obtained after parsing the file.
Note: named imports are not available for JSON modules.
It is also possible to import JSON modules dynamically.
const { default: jsonObject } = await import('./file.json', {
assert: {
type: 'json'
}
});
JavaScriptJSON modules currently work in Node.js >=17.1 by using the –experimental-json-modules flag.
node --experimental-json-modules index.mjs
BashFor browsers, Chrome 91 already has support for JSON modules and others should implement it soon.
While working on a project, I wanted to do an integrity check of a file…
Popovers have been a problem that was typically solved by using a third-party solution. But…
Node.js 20.6 added built-in support for the .env file. This is an excellent addition to the platform…
Object destructuring is a powerful ES 6 feature that can help developers write cleaner code.…
Have you felt particularly annoyed by the time it takes to clone a large repository,…
Within a React or Next.js app, if you encounter the error "Hydration failed because the…