TypeError：Ajv不是构造函数 [英] TypeError: Ajv is not a constructor

问题描述

我在此类中尝试使用new关键字实例化

此代码过去一直有效，这就是Ajv的使用方式。来自Ajv文档：

最快的验证呼叫：

  var Ajv = require（'ajv'）; 
 var ajv = new Ajv（）; //可以传递选项，例如{allErrors：true} 
 var validate = ajv.compile（schema）; 
 var valid = validate（data）; 
 if（！valid）console.log（validate.errors）; 
  

我怎么会收到此错误？

有关如何导入Ajv库-systemjs.config.js的信息，请参见此文章的底部。

 （function（global ）{
 System.config（{
 path：{
 //路径用作别名
'npm：'：'lib / js /'
}，
 //地图告诉系统加载程序在哪里寻找东西
地图：{
 app：'app'，
 //角形包
'@ angular / core' ：'npm：@ angular / core / bundles / core.umd.js'，
'@ angular / common'：'npm：@ angular / common / bundles / common.umd.js'，
 '@ angular / compiler'：'npm：@ angular / compiler / bundles / compiler.umd.js'，
'@ angular / platform-b​​rowser'：'npm：@ angular / platform-b​​rowser / bundles / platform -browser.umd.js'，
'@ angular / platform-b​​rowser-dynamic'：'npm：@ angular / platform-b​​rowser-dynamic / bundles / platform-b​​rowser-dynamic.umd.js'，
 '@ angular / http'：'npm：@ angular / http / bundles / http.umd.js'，
'@ angular / router'：'npm：@ angular / router / bundles / router.umd.js '，
'@ angular / forms'：'npm：@ angular / forms / bundles / forms.umd.js'，
 //其他库
'rxjs'：'npm：rxjs '，
'angular2-in-memory-web-api'：'npm：angular2-in-memory-web-api'，
'angular2-google-maps / core'：'npm：angular2 -google-maps / core / core.umd.js'，
'ajv'：'npm：ajv / dist / ajv.min.js'，
'primeng'：'npm：primeng'
  

解决方案

我看到Ajv具有默认功能，所以我更改了代码：

  let ajv = new Ajv.default（{allErrors：true}）; 
  

不是100％知道那里发生了什么，但是它可以工作。

I have this class where I try to instantiate Ajv with the new keyword and I get this error:

TypeError: Ajv is not a constructor

Code:

import * as Ajv from "ajv";

    export class ValidateJsonService {
        validateJson(json, schema) {
            console.log(Ajv);
            let ajv = new Ajv({ allErrors: true });
            if (!ajv.validate(schema, json)) {
                throw new Error("JSON does not conform to schema: " + ajv.errorsText())
            }
        }
    }

The console log:

This code used to be working and it is how Ajv is used. From the Ajv docs:

The fastest validation call:

var Ajv = require('ajv');
var ajv = new Ajv(); // options can be passed, e.g. {allErrors: true}
var validate = ajv.compile(schema);
var valid = validate(data);
if (!valid) console.log(validate.errors);

How come I'm getting this error?

See the bottom of this for how I import the Ajv library - systemjs.config.js:

(function (global) {
    System.config({
        paths: {
            // paths serve as alias
            'npm:': 'lib/js/'
        },
        // map tells the System loader where to look for things
        map: {
            app: 'app', 
            // angular bundles
            '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
            '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
            '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
            '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
            '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
            '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
            '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
            '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
            // other libraries
            'rxjs': 'npm:rxjs',
            'angular2-in-memory-web-api': 'npm:angular2-in-memory-web-api',
            'angular2-google-maps/core': 'npm:angular2-google-maps/core/core.umd.js',
            'ajv': 'npm:ajv/dist/ajv.min.js',
            'primeng': 'npm:primeng'

解决方案

I saw that Ajv has a default function so I changed my code to this:

let ajv = new Ajv.default({ allErrors: true });

Not 100% sure what is going on there but it works.

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