Live Limit

Need to limit the number of concurrent requests to a server? Or make sure only one function call is running at a time? Live Limit to the rescue!

Docs

See the Live Limit Docs for details.

Install

# with npm
npm install --save live-limit
# with yarn
yarn add live-limit

Requirements

Live Limit requires Promises and Map.values. This is available on everything newer than node.js 12 and any non-IE browser.

If Internet Explorer support is required, consider polyfills.

Example

import { LiveLimit } from "live-limit";

// Setup
// Only allows 3 function calls to be live at a time
const LIMITER = new LiveLimit({ maxLive: 3 });

// Making a single call:
const param = 1;
LIMITER.limit(async () => {
    // code here
});

// Making many calls:
//
// With these limiter settings, the first 3 calls will start immediately.
// The next 3 will pause until one of the earlier calls resolve or reject,
// at which point another call will start.
const params = [1, 2, 3, 4, 5, 6];
params.forEach((param) => {
    LIMITER.limit(async () => {
        myFunc(param);
    });
});

// The async calls can also return a result.
// The promise returned by `LIMITER.limit` will be the result that your function returned.
const out = await LIMITER.limit(async () => {
    return 'foo';
});
console.log(out); // prints 'foo'

Example with Axios, React, and Redux

// ... other imports
import { LiveLimit } from "live-limit";

// 3 concurrent connections at max
const LIMITER = new LiveLimit({ maxLive: 3 });

function SendButton() {
    const dataToSend: any[] = selector((state) => state.data.to.send);
    const [state, setState] = useState<"done" | "loading" | undefined>();

    return (
        <Button
            // Disable button while loading or done
            disabled={state !== undefined}
            // When clicked, make all the requests
            onClick={() => {
                // Disable the button
                setState("loading");
                // Wait until it's done to mark as done
                Promise.all(
                    dataToSend.map(
                        // Creating a promise for each request
                        async (data) => {
                            // Every request goes through the limiter
                            await LIMITER.limit(async () => {
                                await axios.post("/url/to/send/to", data);
                            });
                        }
                    )
                ).then(() => {
                    setState("done");
                });
            }}
        >
            Send all the data
        </Button>
    );
}