Method filter

packages/amis-formula/src/evalutor.ts:102–141

(ast: {
    type: 'filter';
    input: any;
    filters: Array<{name: string; args: Array<any>}>;
  })

  }

  filter(ast: {
    type: 'filter';
    input: any;
    filters: Array<{name: string; args: Array<any>}>;
  }) {
    let input = this.evalute(ast.input);
    const filters = ast.filters.concat();
    const context: FilterContext = {
      filter: undefined,
      data: this.context,
      restFilters: filters
    };

    while (filters.length) {
      const filter = filters.shift()!;
      const fn = this.filters[filter.name];
      if (!fn) {
        throw new Error(`filter \`${filter.name}\` not exists.`);
      }
      context.filter = filter;
      input = fn.apply(
        context,
        [input].concat(
          filter.args.map((item: any) => {
            if (item?.type === 'mixed') {
              return item.body
                .map((item: any) =>
                  typeof item === 'string' ? item : this.evalute(item)
                )
                .join('');
            } else if (item.type) {
              return this.evalute(item);
            }
            return item;
          })
        )
      );
    }
    return input;
  }

  raw(ast: {type: 'raw'; value: string}) {
    return ast.value;