LeftAndMain.js assumes iframe postmessages are strings

[roed]

In LeftAndMain.js, there is a method that handles messages triggered in iframes (postMessage):

$(window).on("message", function(e) {
    var target,
        event = e.originalEvent,
        data = JSON.parse(event.data);

I tried to integrate a third party app that uses such messages, but the event.data is an object, not a string. This causes an error, because it tries to parse an object. Perhaps it is better to check if event.data is a string, and, if so, parse it:

data = typeof event.data == 'string' ? JSON.parse(event.data) : event.data;

[dhensby]

want to open a PR?

[roed]

Was already fixed in 4.0, but still made a PR.

[dhensby]

thanks

[michalkleiner]

Came across a Chrome plugin for Grammarly using this mechanism.
It sends string messages in event.data. The JS here fails to JSON.parse them. The logic needs further strengthening.