使用JSON.stringify报错：Uncaught TypeError: cyclic object value

• 具体错误

Uncaught TypeError: cyclic object value
    onMouseOver Amap.vue:125
    renderMarker Amap.vue:84
    emit maps:1
    emit maps:1
    ci maps:1
    ui maps:1
    fireEvent maps:1
    jL maps:1
    Xt maps:1
    T maps:1
    <anonymous> amap.vue:49
    promise callback*nextTick runtime-core.esm-bundler.js:242
    <anonymous> amap.vue:48
    promise callback* amap.vue:47
    <anonymous> amap.vue:42
    register useRegister.ts:102
    useRegister useRegister.ts:64
    node_modules chunk-A2DP46KH.js:8733
    callWithErrorHandling runtime-core.esm-bundler.js:158
    callWithAsyncErrorHandling runtime-core.esm-bundler.js:166
    __weh runtime-core.esm-bundler.js:2655
    flushPostFlushCbs runtime-core.esm-bundler.js:325
    flushJobs runtime-core.esm-bundler.js:363
    promise callback*queueFlush runtime-core.esm-bundler.js:270
    queueJob runtime-core.esm-bundler.js:264
    reload runtime-core.esm-bundler.js:464
    tryWrap runtime-core.esm-bundler.js:494
    <anonymous> Amap.vue:304
    accept client.ts:564
    fetchUpdate client.ts:481
    queueUpdate client.ts:328
    queueUpdate client.ts:328
    handleMessage client.ts:181
    handleMessage client.ts:179
    setupWebSocket client.ts:96
    setupWebSocket client.ts:95
    <anonymous> client.ts:69
7 Amap.vue:125:35

• 解决办法

输出key和value，检查哪个是object类型，逐个排除。比如我经过输出，判断如下：

const onMouseOver = (event, marker) => {

  let jsonString = JSON.stringify(event, function(key, value) {
    //console.log(key+", "+value);
    if (key === 'target') {
        return undefined; // 忽略循环引用属性
    }
    return value;
  });
  console.log("event="+jsonString);

  jsonString = JSON.stringify(marker, function(key, value) {
    //console.log(key+", "+value);
    if (key === 'context'
      || key === '_map'
      || key == '_parent' ) {
        return undefined; // 忽略循环引用属性
    }
    return value;
  });