How do you check if an API Object is undefined without getting a console error?-CodePudding

I'm using JS & AJAX to gather info from a Web-API (for a crypto-mining pool). Almost all of it works perfectly, but with the server the way the developer set it up, when a value is not used, it MIGHT be empty, not 0. Others do have a placeholder value (I'm talking with the dev to give everything a placeholder, but until then, I need some help).

e.g.:

{"version":"0.0.3","statusCode":200,"headers":{"Access-Control-Allow-Headers":"Content-Type, Access-Control-Allow-Headers, Access-Control-Allow-Origin, Access-Control-Allow-Methods","Access-Control-Allow-Origin":"*","Access-Control-Allow-Methods":"GET","Content-Type":"application/json"},"body":{"primary":{"hashrate":{"shared":0,"solo":0},"payments":{"balances":0,"generate":0,"immature":0,"paid":0},"shares":{"shared":{},"solo":{}},"times":{"shared":0},"work":{"shared":0,"solo":0},"workers":{"shared":[],"solo":[]}},"auxiliary":{"hashrate":{"shared":0,"solo":0},"payments":{"balances":0,"generate":0,"immature":0,"paid":0},"shares":{"shared":{},"solo":{}},"times":{"shared":0},"work":{"shared":0,"solo":0},"workers":{"shared":[],"solo":[]}}}}

You can see that under body.primary.shares.shared it is just [] and not a zero value.

Here is part of the script:

function avianDashboard(api, workerAPI) {
    const xhr = new XMLHttpRequest();
    xhr.open("GET", api, true);
    xhr.onload = function () {
        if (this.status === 200) {
            obj = JSON.parse(this.responseText);
            if (typeof (obj.body.primary.shares.shared) === 'undefined') {
                document.getElementById('minerShares').innerHTML = 0;
            } else {
                document.getElementById('minerShares').innerHTML = obj.body.primary.shares.shared.valid;
            }

//Rest of the function works properly so I've omitted it for the sake of sanity

When I run the page, the console.log shows this..

uncaught TypeError: Cannot read properties of undefined (reading 'shared') at XMLHttpRequest.xhr.onload (avian.php:784:61)

and points to this line:

if (typeof (obj.body.primary.shares.shared) === 'undefined') {

I've found a lot of things that are supposed to help with this issue (including using typeof because I was originally just using <1 or null as my conditional checker and that didn't work either.

Any help would be greatly appreciated.

CodePudding user response：

You can use optional chaining to check if properties of object does exist:

if(obj?.body?.primary?.shares?.shared) {
  ...
}

Check more info here.