Node's processTopLevelAwait

Standalone util function from Node.js core to process await statements in REPL.

Since v10.0.0, Node.js introduced a new experimental feature to support await
keyword in the REPL by using the argument --experimental-repl-await, however,
if a user wants to implement a custom REPL console, there would be no
await-support at all, to achieve such a goal, this package clones the internal
module of await-support to form a standalone version, allowing users share the
benefits of await-support in their own REPL environments.

See
Node.js docs
for more details, and contribute to the
original source.

Example

``javascript
const repl = require("repl");
const vm = require("vm");
const { processTopLevelAwait } = require("node-repl-await");

function isRecoverableError(error) {
if (error.name === 'SyntaxError') {
return /^(Unexpected end of input|Unexpected token)/.test(error.message);
}
return false;
}

async function myEval(code, context, filename, callback) {
code = processTopLevelAwait(code) || code;

try {
let result = await vm.runInNewContext(code, context);
callback(null, result);
} catch (e) {
if (isRecoverableError(e)) {
callback(new repl.Recoverable(e));
} else {
console.log(e);
}
}
}

repl.start({ prompt: '> ', eval: myEval });
`

API

`typescript
function processTopLevelAwait(src: string): string | void
`

Tries to wrap the given source code to an immediately-invoked function if it
contains any top level await statement in the form of

`js
(async () => { / source code / })()
`

If no await presents or processing failed, the function returns null`.