react-mathjax/src/process.js

React component to render math using MathJax

/* @flow */
let pendingScripts = [];
let pendingCallbacks = [];
let needsProcess = false;

/*
 * Process math in a script node using MathJax.
 */
function process(
    MathJax: Object,
    script: HTMLScriptElement,
    callback: () => void
) {
    pendingScripts.push(script);
    pendingCallbacks.push(callback);
    if (!needsProcess) {
        needsProcess = true;
        setTimeout(() => doProcess(MathJax), 0);
    }
}

function doProcess(MathJax: Object) {
    MathJax.Hub.Queue(() => {
        const oldElementScripts = MathJax.Hub.elementScripts;
        MathJax.Hub.elementScripts = element => pendingScripts;

        try {
            return MathJax.Hub.Process(null, () => {
                // Trigger all of the pending callbacks before clearing them
                // out.
                pendingCallbacks.forEach(callback => {
                    callback();
                });

                pendingScripts = [];
                pendingCallbacks = [];
                needsProcess = false;
            });
        } catch (e) {
            // IE8 requires `catch` in order to use `finally`
            throw e;
        } finally {
            MathJax.Hub.elementScripts = oldElementScripts;
        }
    });
}

export default process;