The following error is coming in build time:
src/views/contact-page/contact.page.tsx
Line 25:29: Parsing error: Missing semicolon.
23 | const [test, setTest] = useState<string | null>(null);
24 | setTest("test");
> 25 | const test2: string = test!;
| ^
26 |
Please explain why I could not use not-null assertion operator?
I don't believe this is valid JS (Or typescript) syntax.
const test2: string = test!;
The documentation for TS doesn't list this anywhere as a valid check for null - you can do something like this with objects but I don't believe you can do this for a variable like this.
let s = e!.name; // Assert that e is non-null and access name
Even if that did work, your variable would just be undefined instead of null in the case that test was null.
Related
I am working with typescript react and I need help with how to fix the issue. My constructor object is expecting one of the arguments to be Idl type which is basically a json generated from solana. How do i fix this?
yeah there is a weird thing with TypeScript and the IdlType on args if you look into the IDL object representation.
It is related to this line:
export declare type IdlType = "bool" | "u8" | "i8" | "u16" | "i16" | "u32" | "i32" | "f32" | "u64" | "i64" | "f64" | "u128" | "i128" | "bytes" | "string" | "publicKey" | IdlTypeDefined | IdlTypeOption | IdlTypeCOption | IdlTypeVec | IdlTypeArray;
The way fixed it is by using a workaround:
import YOUR_IDL_JSON_OBJECT from '../config/abiSolana/solanaIDL.json'
const a = JSON.stringify(YOUR_IDL_JSON_OBJECT)
const b = JSON.parse(a)
return new Program(b, address, provider)
When you do this the compiler should not scream at you. If someone cares to explain what the hell is wrong with the enum there, I would be happy. :)
I'm trying to use Microsoft Fabric's UI tools. This is the error I get on my local machine.
/Developer/React/TCV.ts/tcv/src/CategorySelection.tsx(94,9):
Type '(filterText: string, currentPersonas: IPersonaProps[], limitResults?: number | undefined) => IPersonaProps[] | Promise<IPersonaProps[]>' is not assignable to type '(filter: string, selectedItems?: IPersonaProps[] | undefined) => IPersonaProps[] | PromiseLike<IPersonaProps[]>'.
Types of parameters 'currentPersonas' and 'selectedItems' are incompatible.
Type 'IPersonaProps[] | undefined' is not assignable to type 'IPersonaProps[]'.
Type 'undefined' is not assignable to type 'IPersonaProps[]'. TS2322
92 | <CompactPeoplePicker
93 | // eslint-disable-next-line react/jsx-no-bind
> 94 | onResolveSuggestions={onFilterChanged}
| ^
95 | // eslint-disable-next-line react/jsx-no-bind
96 | onEmptyInputFocus={returnMostRecentlyUsed}
97 | getTextFromItem={getTextFromItem}
However, when I load my exact same code to codesandbox.io the error disappears and it works fine. My files are the same, and package.json is identical. What can be causing this behavior?
EXAMPLE:
https://codesandbox.io/s/restless-darkness-xypss?file=/src/Search.tsx
It worked for me also after changing the
"strict": false,
in tsconfig.json
I am trying to write code for a small utility class that detects change in orientation. Unfortunately, the only way I found to access these fields window.orientation and window.screen.orientation
I can see that window.orientation is deprecated. The alternative I found is the experimental detection api that is not supported on Safari. And so I decided to stick to the deprecated apis for now till I find something better.
Now the other challenge I am facing is whilst mocking access to these readonly field
I am facing a similar problem when trying same approach with window.orientation.
Essentially properties we are trying to alter are readonly properties.
What is the correct approach in this situation?
Note the deprecation warning for window.orientation that I see is present in lib.dom.d.ts
You can use Object.defineProperty() to do this.
E.g.
index.ts:
export function main() {
const orientation = window.screen.orientation;
return orientation.type;
}
index.test.ts:
import { main } from './';
describe('63570675', () => {
it('should pass', () => {
Object.defineProperty(window.screen, 'orientation', {
value: { type: 'landscape-primary' },
});
const actual = main();
expect(actual).toEqual('landscape-primary');
});
});
unit test result with coverage report:
PASS src/stackoverflow/63570675/index.test.ts
63570675
✓ should pass (5ms)
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.ts | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 5.292s, estimated 14s
source code: https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/63570675
Failed to Compile: Parsing error unexpected token. The error is on line 20
I am new to React I was following a Brad Traversy tutorial and cant seem to debug this code error. I included the full code below.
./src/Components/AddProject.js
Line 20: Parsing error: Unexpected token
18 | e.preventDefault();
19 | }
> 20 | if(this.refs.title.value === ''){
| ^
21 | alert('Title is required');
22 | } else {
23 | this.setState({newProject:{
You cannot attach flying code in an ES6 JavaScript Class.
It actually doesn't mean anything.
A ES6 Javascript Class will only accept constructor, fields and methods.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes
Are you sure that the code below the line of the syntax error shouldn't be wrapped into a method or into render() ?
I want to sniff only outgoing 'TCP-ACK' packet from my system. Hence I set my filter expression in my lib-pcap program as:
char filter_exp[] = "src host 172.16.0.1 and tcp[tcpflags] & (tcp-syn | tcp-fin | tcp-rst | tcp-psh) == 0";
But it's showing an lib-pcap syntax error at runtime as:
Couldn't parse filter src host 172.16.0.1 and tcp[tcpflags] and (tcp-syn | tcp-fin | tcp-rst | tcp-psh) == 0: syntax error
Can anybody tell what's wrong here and what would be the correct filter expression for this?
I got the syntax from here (in the Examples section.).
The syntax is incorrect because tcp-psh is not a valid syntax. The correct one is tcp-push. So the correct filter expression will be:
char filter_exp[] = "src host 172.16.0.1 and tcp[tcpflags] & (tcp-syn | tcp-fin | tcp-rst | tcp-push) == 0";