Turns out it&#39;s as easy as passing it to the `Number` constructor:

    const myBigInt = BigInt(10);  // `10n` also works
    const myNumber = Number(myBigInt);

Of course, you should bear in mind that your BigInt value must be within [[Number.MIN_SAFE_INTEGER](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MIN_SAFE_INTEGER), [Number.MAX_SAFE_INTEGER](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER)] for the conversion to work properly, as stated in the question.

You can use `parseInt` or `Number`

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    const large =  BigInt(309);
    const b = parseInt(large);
    console.log(b);
    const n = Number(large);
    console.log(n);


&lt;!-- end snippet --&gt;



You should use either of the static methods:

`BigInt.asIntN()` - Clamps a BigInt value to a signed integer value, and returns that value.
`BigInt.asUintN()` - Clamps a BigInt value to an unsigned integer value, and returns that value.

as documented here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt#static_methods

Disclaimer: huge openCV noob

&gt; Traceback (most recent call last):
&gt; 
&gt;   File &quot;lanes2.py&quot;, line 22, in &lt;module&gt;
&gt; 
&gt;     canny = canny(lane_image)
&gt; 
&gt;   File &quot;lanes2.py&quot;, line 5, in canny
&gt; 
&gt;     gray = cv2.cvtColor(imgUMat, cv2.COLOR_RGB2GRAY)
&gt; 
&gt; TypeError: Expected cv::UMat for argument &#39;src&#39;

What exactly is &#39;src&#39; referring to?

OpenCV TypeError: Expected cv::UMat for argument &#39;src&#39; - What is this?

I have a stripe webhook that call a Firebase function. In this function I need to verify that this request comes from Stripe servers. Here is the code :

```typescript
const functions = require(&#39;firebase-functions&#39;);
const bodyParser = require(&#39;body-parser&#39;);
const stripe = require(&quot;stripe&quot;)(&quot;sk_test_****&quot;);
const endpointSecret = &#39;whsec_****&#39;;
const app = require(&#39;express&#39;)();

app.use(bodyParser.json({
    verify: function (req, res, buf) {
        var url = req.originalUrl;
        if (url.startsWith(&#39;/webhook&#39;)) {
            req.rawBody = buf.toString()
        }
    }
}));

app.post(&#39;/webhook/example&#39;, (req, res) =&gt; {
    let sig = req.headers[&quot;stripe-signature&quot;];

    try {
        console.log(req.bodyRaw)
        let event = stripe.webhooks.constructEvent(req.body, sig, endpointSecret);
        console.log(event);
        res.status(200).end()

        // Do something with event
    }
    catch (err) {
        console.log(err);
        res.status(400).end()
    }
});

exports.app = functions.https.onRequest(app);
```

As mentioned in [Stripe Documentation][1], I have to use raw body to perform this security check.

I have tried with my current code and with :

```typescript
app.use(require(&#39;body-parser&#39;).raw({type: &#39;*/*&#39;}));
```

But I always get this error :

    Error: No signatures found matching the expected signature for payload. Are you passing the raw request body you received from Stripe? https://github.com/stripe/stripe-node#webhook-signing

  [1]: https://stripe.com/docs/webhooks/signatures

Stripe Error: No signatures found matching the expected signature for payload

I found myself in the situation where I wanted to convert a `BigInt` value to a `Number` value. Knowing that my value is a [safe integer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger), how can I convert it?

How to convert BigInt to Number in JavaScript?

<p>I found myself in the situation where I wanted to convert a <code>BigInt</code> value to a <code>Number</code> value. Knowing that my value is a <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger" target="_blank" rel="noopener noreferrer">safe integer</a>, how can I convert it?</p>


I am trying to install the necessary dependencies for Exokit, but I am getting an error relating to a Python syntax error.

This is for a something new I wanted to try involving VR in the browser. I&#39;ve recloned the repository from their github and downloaded straight from their website. I followed the instructions given to a T (there was only 4 of them lol).

    I have not yet touched the code and this is the error that I am getting.

    Austin@DESKTOP-UD2R1O4 MINGW64 ~/exokit (master)
    $ npm install
    
    &gt; raw-buffer@0.0.19 install C:\Users\Austin\exokit\node_modules\raw-buffer
    &gt; node-gyp rebuild


    C:\Users\Austin\exokit\node_modules\raw-buffer&gt;if not defined 
    npm_config_node_gyp (node &quot;C:\Program 
    Files\nodejs\node_modules\npm\node_modules\npm-lifecycle\node-gyp- 
    bin\\..\..\node_modules\node-gyp\bin\node-gyp.js&quot; rebuild )  else (node 
    &quot;C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\bin\node-gyp.js&quot; rebuild )
    gyp ERR! configure error
    gyp ERR! stack Error: Command failed: C:\Users\Austin\Anaconda3\python.EXE -c import sys; print &quot;%s.%s.%s&quot; % sys.version_info[:3];
    gyp ERR! stack   File &quot;&lt;string&gt;&quot;, line 1
    gyp ERR! stack     import sys; print &quot;%s.%s.%s&quot; % sys.version_info[:3];
    gyp ERR! stack                                ^
    gyp ERR! stack SyntaxError: invalid syntax
    gyp ERR! stack
    gyp ERR! stack     at ChildProcess.exithandler (child_process.js:276:12)
    gyp ERR! stack     at emitTwo (events.js:126:13)
    gyp ERR! stack     at ChildProcess.emit (events.js:214:7)
    gyp ERR! stack     at maybeClose (internal/child_process.js:915:16)
    gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:209:5)
    gyp ERR! System Windows_NT 10.0.17134
    gyp ERR! command &quot;C:\\Program Files\\nodejs\\node.exe&quot; &quot;C:\\Program Files\\nodejs\\node_modules\\npm\\node_modules\\node-gyp\\bin\\node-gyp.js&quot; &quot;rebuild&quot;
    gyp ERR! cwd C:\Users\Austin\exokit\node_modules\raw-buffer
    gyp ERR! node -v v8.12.0
    gyp ERR! node-gyp -v v3.8.0
    gyp ERR! not ok
    npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.4 (node_modules\fsevents):
    npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.4: wanted {&quot;os&quot;:&quot;darwin&quot;,&quot;arch&quot;:&quot;any&quot;} (current: {&quot;os&quot;:&quot;win32&quot;,&quot;arch&quot;:&quot;x64&quot;})

    npm ERR! code ELIFECYCLE
    npm ERR! errno 1
    npm ERR! raw-buffer@0.0.19 install: `node-gyp rebuild`
    npm ERR! Exit status 1
    npm ERR!
    npm ERR! Failed at the raw-buffer@0.0.19 install script.
    npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

    npm ERR! A complete log of this run can be found in:
    npm ERR!     C:\Users\Austin\AppData\Roaming\npm-cache\_logs\2019-01-06T06_55_37_752Z-debug.log



After `npm install` an error about a syntax error in python appears?

I am trying to learn hooks and the `useState` method has made me confused. I am assigning an initial value to a state in the form of an array. The set method in `useState` is not working for me, both with and without the spread syntax.

I have made an API on another PC that I am calling and fetching the data which I want to set into the state.

Here is my code:

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-html --&gt;

    &lt;div id=&quot;root&quot;&gt;&lt;/div&gt;

    &lt;script type=&quot;text/babel&quot; defer&gt;
    // import React, { useState, useEffect } from &quot;react&quot;;
    // import ReactDOM from &quot;react-dom&quot;;
    const { useState, useEffect } = React; // web-browser variant

    const StateSelector = () =&gt; {
      const initialValue = [
        {
          category: &quot;&quot;,
          photo: &quot;&quot;,
          description: &quot;&quot;,
          id: 0,
          name: &quot;&quot;,
          rating: 0
        }
      ];

      const [movies, setMovies] = useState(initialValue);

      useEffect(() =&gt; {
        (async function() {
          try {
            // const response = await fetch(&quot;http://192.168.1.164:5000/movies/display&quot;);
            // const json = await response.json();
            // const result = json.data.result;
            const result = [
              {
                category: &quot;cat1&quot;,
                description: &quot;desc1&quot;,
                id: &quot;1546514491119&quot;,
                name: &quot;randomname2&quot;,
                photo: null,
                rating: &quot;3&quot;
              },
              {
                category: &quot;cat2&quot;,
                description: &quot;desc1&quot;,
                id: &quot;1546837819818&quot;,
                name: &quot;randomname1&quot;,
                rating: &quot;5&quot;
              }
            ];
            console.log(&quot;result =&quot;, result);
            setMovies(result);
            console.log(&quot;movies =&quot;, movies);
          } catch (e) {
            console.error(e);
          }
        })();
      }, []);

      return &lt;p&gt;hello&lt;/p&gt;;
    };

    const rootElement = document.getElementById(&quot;root&quot;);
    ReactDOM.render(&lt;StateSelector /&gt;, rootElement);
    &lt;/script&gt;

    &lt;script src=&quot;https://unpkg.com/@babel/standalone@7/babel.min.js&quot;&gt;&lt;/script&gt;
    &lt;script src=&quot;https://unpkg.com/react@17/umd/react.production.min.js&quot;&gt;&lt;/script&gt;
    &lt;script src=&quot;https://unpkg.com/react-dom@17/umd/react-dom.production.min.js&quot;&gt;&lt;/script&gt;


&lt;!-- end snippet --&gt;

Neither `setMovies(result)` nor `setMovies(...result)` works.

I expect the `result` variable to be pushed into the `movies` array.





The useState set method is not reflecting a change immediately

I am using react `useEffect` hooks and checking if an object has changed and only then run the hook again.

My code looks like this.

    const useExample = (apiOptions) =&gt; {
    	const [data, updateData] = useState([]);
    	useEffect(() =&gt; {
    	   const [data, updateData] = useState&lt;any&gt;([]);
    		doSomethingCool(apiOptions).then(res =&gt; {               
               updateData(response.data);
           })
    	}, [apiOptions]);
    
    	return {
    		data
    	};
    };

Unfortunately it keeps running as the objects are not being recognised as being the same.

I believe the following is an example of why.

&lt;!-- begin snippet: js hide: false console: true babel: false --&gt;

&lt;!-- language: lang-js --&gt;

    const objA = {
       method: &#39;GET&#39;
    }

    const objB = {
       method: &#39;GET&#39;
    }

    console.log(objA === objB)

&lt;!-- end snippet --&gt;

Perhaps running `JSON.stringify(apiOptions)` works?



react useEffect comparing objects

In a JavaScript ES6-module, there may be many, small, easy-to-test functions that should be tested, but shouldn&#39;t be exported. How do I test functions in a module without exporting them? (without using [Rewire][1]).

  [1]: https://github.com/jhnns/rewire#limitations





How can I unit test non-exported functions?

In the past, we&#39;ve been explicitly warned that calling `setState({myProperty})` is asynchronous, and the value of `this.state.myProperty` is not valid until the callback, or until the next `render()` method.

**With useState, how do I get the value of the state after explicitly updating it?**


How does this work with hooks? As far as I can tell, the setter function of `useState` doesn&#39;t take a callback, e.g.

    const [value, setValue] = useState(0);
    setValue(42, () =&gt; console.log(&#39;hi callback&#39;);

doesn&#39;t result in the callback being run.

My other workaround in the old world is to hang an instance variable `(e.g. this.otherProperty = 42)` on the class, but that doesn&#39;t work here, as there is no function instance to reuse (no `this` in strict mode).


Is useState synchronous?

Rust has 128-bit integers, these are denoted with the data type `i128` (and `u128` for unsigned ints):

    let a: i128 = 170141183460469231731687303715884105727;

How does Rust make these `i128` values work on a 64-bit system; e.g. how does it do arithmetic on these?

Since, as far as I know, the value cannot fit in one register of a x86-64 CPU, does the compiler somehow use two registers for one `i128` value? Or are they instead using some kind of big integer struct to represent them?

How does Rust&#39;s 128-bit integer `i128` work on a 64-bit system?

 I&#39;ve come across the term `ESNext`, and wondering it is the same as the ECMAScript.

So, I have these questions here: 

 - What is ESNext, actually? 
 - Does it refer to any specific version of ECMAScript?

Content Type	Original Author	Original Content on Stackoverflow
Question	Lucio Paiva	View Question on Stackoverflow
Solution 1 - Javascript	Lucio Paiva	View Answer on Stackoverflow
Solution 2 - Javascript	I_Al-thamary	View Answer on Stackoverflow
Solution 3 - Javascript	zr0gravity7	View Answer on Stackoverflow

How to convert BigInt to Number in JavaScript?

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

Solution 3 - Javascript

Stripe Error: No signatures found matching the expected signature for payload

OpenCV TypeError: Expected cv::UMat for argument 'src' - What is this?

Attributions