fix: adjust types in autocomplete-display-example #9240
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rafaelss95
commented
Jan 5, 2018
rafaelss95
commented
googlebot
added
the
cla: yes
| startWith({} as User), | ||
| map(user => user && typeof user === 'object' ? user.name : user), | ||
| startWith<string | User>(this.myControl.value), | ||
| map(value => value && typeof value === 'object' ? value.name : value as string), |
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as was necessary to run properly on Stackblitz.
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The typeof something === 'object' is a little tricky since it'll also be true for null. This might be nicer if you changed it to:
return typeof value === 'string' ? value : value.name;There was a problem hiding this comment.
"The typeof something === 'object' is a little tricky since it'll also be true for null"
In this case, it won't happen because the check is value && typeof value === 'object'. Anyway, I changed it since it's more readable.
| displayFn(user: User): string { | ||
| return user ? user.name : user; | ||
| displayFn(user?: User): string | undefined { | ||
| return user ? user.name : undefined; |
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I was doing the following:
displayFn(user?: User): string | undefined {
return user ? user.name : user; <---
}
... however it doesn't go well in Stackblitz (maybe because there we don't have strictNullChecks).
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The class |
| @@ -31,8 +31,8 @@ export class AutocompleteDisplayExample { | |||
| ngOnInit() { | |||
| this.filteredOptions = this.myControl.valueChanges | |||
| .pipe( | |||
| startWith({} as User), | |||
| map(user => user && typeof user === 'object' ? user.name : user), | |||
| startWith<string | User>(this.myControl.value), | |||
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myControl.value will always be undefined. You could start it off with an empty string instead.
| startWith({} as User), | ||
| map(user => user && typeof user === 'object' ? user.name : user), | ||
| startWith<string | User>(this.myControl.value), | ||
| map(value => value && typeof value === 'object' ? value.name : value as string), |
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The typeof something === 'object' is a little tricky since it'll also be true for null. This might be nicer if you changed it to:
return typeof value === 'string' ? value : value.name;
|
Out of curiosity, can someone explain why these errors weren't caught by the compiler? |
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