Typescript can i use generic type in function body
1
i have function declaration like this:
export const filterOptions: <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) => OptionsArray<OptionValueType> = (options, filterBy) =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
but, typescript mark this code as Error, can we use generic types in function body ?
const filteredOptions: OptionsArray<OptionValueType> = ;
TS2304: Cannot find name 'OptionValueType'
typescript
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
add a comment |
1
i have function declaration like this:
export const filterOptions: <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) => OptionsArray<OptionValueType> = (options, filterBy) =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
but, typescript mark this code as Error, can we use generic types in function body ?
const filteredOptions: OptionsArray<OptionValueType> = ;
TS2304: Cannot find name 'OptionValueType'
typescript
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
add a comment |
1
1
1
0
i have function declaration like this:
export const filterOptions: <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) => OptionsArray<OptionValueType> = (options, filterBy) =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
but, typescript mark this code as Error, can we use generic types in function body ?
const filteredOptions: OptionsArray<OptionValueType> = ;
TS2304: Cannot find name 'OptionValueType'
typescript
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
i have function declaration like this:
export const filterOptions: <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) => OptionsArray<OptionValueType> = (options, filterBy) =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
but, typescript mark this code as Error, can we use generic types in function body ?
const filteredOptions: OptionsArray<OptionValueType> = ;
TS2304: Cannot find name 'OptionValueType'
typescript
typescript
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
asked Nov 15 '18 at 13:10
Евгений ЛитвиненкоЕвгений Литвиненко
2915
2915
add a comment |
add a comment |
1 Answer
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You can use the generic type parameter in the body, but the generic type parameter has to be on the function implementation not on the variable that will hold the function
export const filterOptions = <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) : OptionsArray<OptionValueType> =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
1
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
add a comment |
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1 Answer
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active
oldest
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active
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oldest
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0
You can use the generic type parameter in the body, but the generic type parameter has to be on the function implementation not on the variable that will hold the function
export const filterOptions = <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) : OptionsArray<OptionValueType> =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
1
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
add a comment |
0
You can use the generic type parameter in the body, but the generic type parameter has to be on the function implementation not on the variable that will hold the function
export const filterOptions = <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) : OptionsArray<OptionValueType> =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
1
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
add a comment |
0
0
0
You can use the generic type parameter in the body, but the generic type parameter has to be on the function implementation not on the variable that will hold the function
export const filterOptions = <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) : OptionsArray<OptionValueType> =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
You can use the generic type parameter in the body, but the generic type parameter has to be on the function implementation not on the variable that will hold the function
export const filterOptions = <OptionValueType>(options: OptionsArray<OptionValueType>, filterBy: string) : OptionsArray<OptionValueType> =>
if (filterBy === '')
return [...options];
else
const filteredOptions: OptionsArray<OptionValueType> = ;
// filter and return options
return [...filteredOptions];
;
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
answered Nov 15 '18 at 13:54
Titian Cernicova-DragomirTitian Cernicova-Dragomir
70.2k34866
70.2k34866
1
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
add a comment |
1
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
1
1
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
You save my day! Thank you.
– Евгений Литвиненко
Nov 15 '18 at 14:21
add a comment |
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