如何修改管道以删除重复的条目？

Question

我有以下 JSON 文件：http://pastebin.com/1TguvZXc

遍历数组可以找到数组中重复的'body'：

models[x].years[y].styles[z].submodel.body

换句话说：

 models[0].years[0].styles[0].submodel.body

应检查重复项：

models[0].years[0].styles[1].submodel.body  
models[0].years[0].styles[2].submodel.body  
models[0].years[0].styles[n].submodel.body

其余的数据对我来说没用。

我有以下管道：

import { Pipe, PipeTransform } from '@angular/core';
@Pipe({
  name: 'filterByCategory'
})
export class FilterByCategoryPipe implements PipeTransform {

  transform(input: any , search: string): any[] {
    if (input === undefined || input.length === 0) {
      return input;
    }

    const filteredArr: Array<any> = JSON.parse(JSON.stringify(input));

    for (const model of filteredArr) {
      for (const year of model.years) {
        year.styles = year.styles.filter(style => {
          return style.submodel.body === search;
        });
        }
      }


    return filteredArr;
  }

}

我如何向我的 .filter 函数添加额外的 'test' 以检查 'submodel.body' 的值是否存在于任何样式数组中？

Answer 1

基本上，您需要使用filter函数来删除重复的元素。

因此，删除重复项的函数如下所示并使用 indexOf 函数

function removeDuplicate(element, index, array) {
                return array.map(style => style.submodel.body).indexOf(element.submodel.body) === index;
            }

以下是代码的 JS 版本，您可以使用它并为 post 中定义的 search 添加 where 条件。

function removeDuplicate(element, index, array) {
            return array.map(style => style.submodel.body).indexOf(element.submodel.body) === index;
        }

var data = '{"models":[{"id":"Acura_ILX","name":"ILX","niceName":"ilx","years":[{"id":401640361,"year":2017,"styles":[{"id":401640368,"name":"AcuraWatch Plus Package 4dr Sedan (2.4L 4cyl 8AM)","submodel":{"body":"Sedan","modelName":"ILX Sedan","niceName":"sedan"},"trim":"AcuraWatch Plus Package"},{"id":401640367,"name":"Technology Plus and A-SPEC Packages 4dr Sedan (2.4L 4cyl 8AM)","submodel":{"body":"Sedan","modelName":"ILX Sedan","niceName":"sedan"},"trim":"Technology Plus and A-SPEC Packages"},{"id":401640366,"name":"Premium Package 4dr Sedan (2.4L 4cyl 8AM)","submodel":{"body":"Sedan","modelName":"ILX Sedan","niceName":"sedan"},"trim":"Premium Package"},{"id":401640365,"name":"Premium and A-SPEC Packages 4dr Sedan (2.4L 4cyl 8AM)","submodel":{"body":"Sedan","modelName":"ILX Sedan","niceName":"sedan"},"trim":"Premium and A-SPEC Packages"},{"id":401640364,"name":"Technology Plus Package 4dr Sedan (2.4L 4cyl 8AM)","submodel":{"body":"Sedan","modelName":"ILX Sedan","niceName":"sedan"},"trim":"Technology Plus Package"},{"id":401640363,"name":"4dr Sedan (2.4L 4cyl 8AM)","submodel":{"body":"Sedan","modelName":"ILX Sedan","niceName":"sedan"},"trim":"Base"}]}]},{"id":"Acura_NSX","name":"NSX","niceName":"nsx","years":[{"id":200779937,"year":2017,"styles":[{"id":101418796,"name":"2dr Coupe AWD (3.5L 6cyl Turbo gas/electric hybrid 9AM)","submodel":{"body":"Coupe","modelName":"NSX Coupe","niceName":"coupe"},"trim":"Base"}]}]}],"modelsCount":6}';


var jsonData = JSON.parse(data);
jsonData.models.forEach(model => 
                         model.years.forEach(year => 
   year.styles = year.styles.filter(removeDuplicate)  
   ));
console.log(jsonData);

如何修改管道以删除重复的条目？

How to modify pipe to remove duplicate entries?

javascript

arrays

angular

typescript

angular-pipe