承诺错误：对象作为React子项无效

Question

我试图使用用户代理将json设置为一个状态，我得到错误：

Uncaught Invariant Violation：对象无效作为React子对象（找到：带有键{...}的对象）。如果您要渲染子集合，请使用数组，或使用React附加组件中的createFragment（object）包装对象。

method to set state:

 getInitialState: function(){
    return {
        arrayFromJson: []
    }
},

loadAssessmentContacts: function() {
    var callback = function(data) {
        this.setState({arrayFromJson: data.schools})
    }.bind(this);

    service.getSchools(callback);
},

componentWillMount: function(){
    this.loadAssessmentContacts();
},

onTableUpdate: function(data){

    console.log(data);

},

render: function() {

    return (
        <span>{this.state.arrayFromJson}</span>
    );
}

service

getSchools : function (callback) {
        var url = 'file.json';
       request
            .get(url)
            .set('Accept', 'application/json')
            .end(function (err, res) {
                if (res && res.ok) {
                    var data = res.body;
                    callback(data);

                } else {
                    console.warn('Failed to load.');
                }
            });
    }

Json

{
"schools": [
{
  "id": 4281,
  "name": "t",
  "dfe": "t",
  "la": 227,
  "telephone": "t",
  "address": "t",
  "address2": "t",
  "address3": "t",
  "postCode": "t",
  "county": "t",
  "ofsted": "t",
  "students": 2,
  "activeStudents": 2,
  "inActiveStudents": 0,
  "lastUpdatedInDays": 0,
  "deInstalled": false,
  "inLa": false,
  "status": "unnassigned",
  "authCode": "t",
  "studentsActivity": 0
},......
]}