我收到此错误ERROR TypeError:使用此角形管道时无法读取null错误的属性'split',这是代码。
import { Pipe, PipeTransform } from '@angular/core';
@Pipe({
name: 'fullDate'
})
export class DatePipe implements PipeTransform {
transform(value:any ) {
const dateArray = value.split('-');
const date = dateArray[2].substr(0, 1) === '0' ? dateArray[2].substr(1, 1) : dateArray[2];
const months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];
return `${date} ${months[dateArray[1] - 1]} ${dateArray[0]}`;
}
}
{{lorem?.lorem_date | fullDate}}
在管道中添加null
检查:
import { Pipe, PipeTransform } from '@angular/core';
@Pipe({
name: 'fullDate'
})
export class DatePipe implements PipeTransform {
transform(value: any) {
if (value) {
const dateArray = value.split('-');
const date = dateArray[2].substr(0, 1) === '0' ? dateArray[2].substr(1, 1) : dateArray[2];
const months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];
return `${date} ${months[dateArray[1] - 1]} ${dateArray[0]}`;
}
return value;
}
}
将内容放入*ngIf
:
<p *ngIf="lorem">{{ lorem.lorem_date | fullDate }}</p>
基本上,您的代码中发生的事情是,当它第一次运行时,值varible没有分配任何值。因为它会返回并错误提示Cannot read property 'split' of null
验证管道内的值是否具有值。请在下面找到示例代码:
import { Pipe, PipeTransform } from '@angular/core';
@Pipe({
name: 'fullDate'
})
export class DatePipe implements PipeTransform {
transform(value:any ) {
if(value){
const dateArray = value.split('-');
const date = dateArray[2].substr(0, 1) === '0' ? dateArray[2].substr(1, 1) : dateArray[2];
const months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];
return `${date} ${months[dateArray[1] - 1]} ${dateArray[0]}`;
}
}
错误意味着您正在分割一个空值,因此您只需添加一个检查即可。
尝试这样:
transform(value:any ) {
if(value){
const dateArray = value.split('-');
const date = dateArray[2].substr(0, 1) === '0' ? dateArray[2].substr(1, 1) : dateArray[2];
const months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];
return `${date} ${months[dateArray[1] - 1]} ${dateArray[0]}`;
}
}