Node.js ERROR: (node:9748) UnhandledPromiseRejectionWarning: Unhandled promise rejection - json

Question

I'm trying to get a json from "nightmare" in Node.js and then use JSON.parse(), but I'm getting the following error:
(node:9748) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): SyntaxError: Unexpected token ☻ in JSON at position 18509
My code:
var nightmare = Nightmare()
.goto('URL')
.wait(10000) // Need wait some time
.evaluate(() => {
return document.body.innerText;
})
.end()
.then((body) => {
var data;
try {
data = JSON.parse(body);
} catch(e) {
console.log(e);
}
callback(null, data);
});

Answer 1

You can check if the JSON is valid or not simply using the JSON.parse function as you are using.
function validJSON(str) {
try {
// try to parse the JSON
JSON.parse(str);
} catch (e) {
// if not a json
return false;
}
// if it's valid json
return true;
}
It'll check if the string is valid json or not. Now, you can use it with your nightmareJS.
const nightmare = Nightmare()
.goto("URL")
.wait(10000) // Need wait some time
.evaluate(() => {
return document.body.innerText;
})
.end()
.then(body => {
// if it's a valid json, send it,
// otherwise send it as a body object
const data = validJSON(body) ? body : { body };
callback(null, data);
});
Now, the error is showing because you said to catch(e) and console.log(e) the error. Thus it's simply obeying your command.
Since the emoji itself is not a valid json, you have to either make a json from it, or parse it if it was a json string.
A valid json object might look like this,
{emoji: "☻"}
You see how it's all quoted?