使用slice pipe (angular的核心管道)非常简单，就像你要求data.title一样:

{{ data.title | slice:0:20 }}

来自Angular通用文档https://angular.io/api/common/SlicePipe

两种方法将文本截断成角。

let str = 'How to truncate text in angular';

1. 解决方案

  {{str | slice:0:6}}

输出:

   how to

如果你想在切片字符串之后追加任何文本，比如

   {{ (str.length>6)? (str | slice:0:6)+'...':(str) }}

输出:

 how to...

2. 解决方案(创建自定义管道)

如果要创建自定义截断管道

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
 name: 'truncate'
})

export class TruncatePipe implements PipeTransform {

transform(value: string, args: any[]): string {
    const limit = args.length > 0 ? parseInt(args[0], 10) : 20;
    const trail = args.length > 1 ? args[1] : '...';
    return value.length > limit ? value.substring(0, limit) + trail : value;
   }
}

在标记

{{ str | truncate:[20] }} // or 
{{ str | truncate:[20, '...'] }} // or

不要忘记添加一个模块条目。

@NgModule({
  declarations: [
    TruncatePipe
  ]
})
export class AppModule {}

您可以根据CSS截断文本。它有助于根据宽度截断文本，而不是固定字符。

例子

CSS

.truncate {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.content {
    width:100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

HTML

<div class="content">
    <span class="truncate">Lorem Ipsum is simply dummied text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</span>
</div>

注意:这段代码一行使用full，而不是多行。

如果你想用Angular来做，那么Ketan的解决方案是最好的

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'truncate',
})
export class TruncatePipe implements PipeTransform {
  transform(value: string, limit: number, trail = '...'): string {
    if (value.length <= limit) {
      return value;
    }

    return value.substring(0, limit - trail.length).replace(/\s+$/, '') + trail;
  }
}

{{ str | truncate: 20 }}
{{ str | truncate: 20:'>>>'] }}

如果需要用单词截断:

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'truncateByWords',
})
export class TruncateByWordsPipe implements PipeTransform {
  transform(value: string, limit: number, trail = '...'): string {
    if (value.length <= limit) {
      return value;
    }

    const substr = value.substring(0, limit - trail.length).split(' ');
    const isLastWordFull = value
      .split(' ')
      .find(w => w === substr[substr.length - 1]);

    if (isLastWordFull) {
      return substr.join(' ') + trail;
    }

    return substr.slice(0, -1).join(' ') + trail;
  }
}

{{ str | truncateByWords: 20 }}
{{ str | truncateByWords: 20:'>>>'] }}

用省略号截断字符串

不需要任何额外的管道，你可以使用切片。

{{ stringText | slice: 0:25}} {{ stringText.length > 25 ? '...' : ''}}

用可选参数截断管道:

Limit - string最大长度 completeWords -标记在最近的完整单词处截断，而不是字符 省略号——附加在后面的后缀

-

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'truncate'
})
export class TruncatePipe implements PipeTransform {
  transform(value: string, limit = 25, completeWords = false, ellipsis = '...') {
    if (completeWords) {
      limit = value.substr(0, limit).lastIndexOf(' ');
    }
    return value.length > limit ? value.substr(0, limit) + ellipsis : value;
  }
}

不要忘记添加一个模块条目。

@NgModule({
  declarations: [
    TruncatePipe
  ]
})
export class AppModule {}

使用

示例字符串:

public longStr = 'A really long string that needs to be truncated';

标记:

  <h1>{{longStr | truncate }}</h1> 
  <!-- Outputs: A really long string that... -->

  <h1>{{longStr | truncate : 12 }}</h1> 
  <!-- Outputs: A really lon... -->

  <h1>{{longStr | truncate : 12 : true }}</h1> 
  <!-- Outputs: A really... -->

  <h1>{{longStr | truncate : 12 : false : '***' }}</h1> 
  <!-- Outputs: A really lon*** -->