feat(MatTable) Add `sortPredicate` to MatTableDataSource or MatSort
- Lenguaje dominante
- TypeScript
- Estrellas
- 25k
- Forks
- 6.8k
- Merge medio
- 1 d 8 h
- PR fusionados (30 d)
- 91
Descripción
### Feature Description
`MatTableDataSource` already has a `filterPredicate` property that allows you to pass a function with the signature `(data: T, filter: string) => boolean` to implement a custom filtering algorithm. This makes it much easier to control the behavior of the table when passing a filter value to the data source.
The same thing is not possible when sorting: currently, the only way to control the behavior of a `MatSort` on a `MatTableDataSource` is to set its `sortingDataAccessor` property. And this is extremely limited because it only allows to control what the sorting algorithm "sees" and not how it sorts the data.
Proposition:
Add a `sortPredicate` analogous to `MatTableDataSource.filterPredicate` to either `MatTableDataSource` or `MatSort`.
This property would accept a function with the signature `(a: T, b: T, sort: Sort) => number` to mirror the signature of the comparison function passed to `Array.sort`.
An alternative would be a signature like `(sort: Sort) => (a: T, b: T) => number` which would return a comparison function derived the current sorting key/order.
Note that it would be better to be able to override the sort comparison function of only certain columns, in this case a possible solution would be to accept a function with the signature `(sort: Sort) => ((a: T, b: T) => number) | undefined` and fallback to the default comparison function on `undefined`.
This property would give a lot more control over the sorting algorithm to the user than what is currently possible.
### Use Case
There is no easy way to customize the sorting algorithm, for ex: https://stackoverflow.com/q/55016642/10061195
This property would also make it easier to sort nested objects. Currently, this needs to either give a specific name to the column to sort, or to catch the data access using `sortingDataAccessor`.
For example, a solution to the given SO question using the proposed property would be:
```ts
dataSource.sortPredicate = (sort: Sort) => {
if (sort.active === 'code') {
if (sort.direction === 'asc') {
return (a, b) => a.localeCompare(b, undefined, { numeric: true });
} else {
return (a, b) => b.localeCompare(a, undefined, { numeric: true });
}
}
};
```
or
```ts
// JS/TS does not support array as keys in object / Map
const compare = {
'code#asc': (a, b) => a.localeCompare(b, undefined, { numeric: true }),
'code#desc': (a, b) => b.localeCompare(a, undefined, { numeric: true }),
};
dataSource.sortPredicate = (sort: Sort) => compare[sort.active + '#' + sort.direction];
```
Guía de contribución
Línea de trabajo
Comienza con MatTableDataSource y MatSort, comparando el comportamiento existente de filterPredicate y sortingDataAccessor. Revisa las firmas de comparator propuestas y el fallback específico por columna antes de elegir una forma de API. La tarea está terminada cuando se puede aplicar una ordenación personalizada y la ordenación predeterminada existente sigue estando disponible.
Escrito por el modelo de indexación a partir del texto del issue.
Evaluación
- Stack tecnológico
- angular, typescript
- Área
- frontend
- Tipo de issue
- Nueva funcionalidad
- Dificultad
- 5/5
- Tiempo estimado
- Más de una semana
- Estado de actividad
- Estancado
- Claridad
- Bastante claro
- Aptitud para principiantes
- 35/100