typescript Angular，TypeError：无法读取未定义的属性“toLowerCase”
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Angular, TypeError: Cannot read property 'toLowerCase' of undefined
提问by Wira Xie
i'm trying to make a custom filter pipe by following this link, but i got error that said Angular, TypeError: Cannot read property 'toLowerCase' of undefined. I already imported the pipe to app.module.tsand also declared it in declaration. Can anyone help me with this error?
我正在尝试按照此链接制作自定义过滤器管道，但出现错误提示Angular, TypeError: Cannot read property 'toLowerCase' of undefined。我已经将管道导入app.module.ts并在declaration. 谁能帮我解决这个错误？
<form id="filter">
<input type="text" class="form-control" name="term" [(ngModel)]="term" placeholder="filter by name" />
</form>
<tr *ngFor="let product of productList | paginate: { itemsPerPage: 1, currentPage: p } | filter: term">
<td>{{product.prdName}}</td>
<td>{{product.prdCat}}</td>
<td>{{product.prdSup}}</td>
</tr>@Pipe({
name: 'filter'
})
transform(prdName: any, term: any): any {
if (term === undefined) return prdName;
return prdName.filter(function(Product) {
return Product.name.toLowerCase().includes(term.toLowerCase());
})回答by Chandru
try like this :
试试这样：
transform(items: any, term: any): any {
if (term === undefined) return items;
return items.filter(function(Product) {
return Product.prdName.toLowerCase().includes(term.toLowerCase());
})
}
回答by Christian Benseler
Is the attribute called 'name' or 'prdName' (the one you used in the template is 'prdName')?
属性是“name”还是“prdName”（您在模板中使用的那个是“prdName”）？
transform(values, args) {
values.filter(
product => product.prdName.toLowerCase().includes(args.toLowerCase())
)
}
