为什么 JSON.parse() 不解析这个？

Question

我有 JSON 数据，我正在尝试使用 JSON.parse() 解析它。我不断收到错误消息：unexpected token o。有人可以帮忙吗？我觉得我应该提到我将使用解析的 JSON 数据来填充 Dojo 存储，然后将用于填充 Dijit 树。有人会推荐任何其他方法来形成树吗UI？

这是我的代码。

$(document).ready(function(){

require([
"dojo/ready", "dojo/_base/window", "dojo/json","dojo/dom","dojo/store/Memory", "dojo/store/Observable",
"dijit/tree/ObjectStoreModel", "dijit/Tree", "dojo/domReady!", "dojo/mouse","dojo/text!./data/all.json"],
 function(ready, win, JSON, dom, Memory, Observable, ObjectStoreModel, Tree, mouse, data){

var testStore = new Memory({

    data :  JSON.parse($("#getData").click(
            function(){
                  var inputString = "pspTreegetData{}";
                  var state =  Function that executes Tcl script and returns the JSON data
                  return state;
            })),

这是我的 Tcl 脚本，当我检查其输出时，它会提供原始 JSON 数据，

proc pspTreegetData {} {
            set fo [open "C:/Path/To/File/sampleTest.json" r]
            set text [read $fo]
            close $fo
            puts $text 
            return $text
}

我的Json文件如下，

 [
{
    "name" : "root",
    "id"   : "rootNode",
    "description" : "This is the root node"
},

{
    "name"  : "level1_node1",
    "id"    : "l1n1", 
    "description" : "This is the first node of level 1",
    "parent" : "rootNode"
},

    { 
        "name"  : "level2_node1",
        "id"    :  "l2n1",
        "description" : "This is the first node of level 2",
        "parent" : "l1n1"
    },

    { 
        "name"  : "level2_node2",
        "id"    : "l2n2",
        "description" : "This is the second node of level 2",
        "parent" : "l1n1"
    },

        { 
            "name"    : "level3_node1",
            "id"      : "l3n1",
            "description" : "This is the first node of level 3",
            "parent" : "l2n2"
        },

        {
            "name"    : "level3_node2",
            "id"      : "l3n2",
            "description" : "This is the second node of level 3",
            "parent" : "l2n2"
        },

{ 
        "name"  : "level1_node2",
        "id"    : "l1n2",
        "description" : "This is the second node of level 1",
        "parent" : "rootNode"
},

{ 
        "name"  : "level1_node3",
        "id"    :  "l1n3",
        "description" : "This is the third node of level 1",
        "parent" : "rootNode"
},
        { 
            "name"  : "level2_node3",
            "id"    : "l2n3",
            "description" : "This is the third node of level 2",
            "parent" : "l1n3"
        },

        { 
            "name"  : "level2_node4",
            "id"    : "l2n4",
            "description" : "This is the fourth node of level 2",
            "parent" : "l1n3"
        },


{ 
        "name"  : "level1_node4",
        "id"   : "l1n4",
        "description" : "This is the fourth node of level 1",
        "parent" : "rootNode"
}
]

Answer 1

I keep getting the error : unexpected token o.

这意味着您正在尝试解析已解析的对象。只需删除 JSON.parse() 并按原样使用输入数据。

为什么"token o"？因为 JSON.parse() 在提供的输入上运行 toString() 方法以确保它确实是 String 类型。但是，当在对象 toString() 上调用时会生成一个字符串 "[object Object]"。第一个字符看起来像数组，但第二个字符绝对不是可解析的。因此错误。

UPD. 当您尝试解析 jQuery 实例对象时，您会严重混淆事情 - 因为这就是您编写 JSON.parse($("#getData").click()); 时发生的情况。尽管事件对象中有 return state 行，但您 不能从事件侦听器函数中 return，因为它没有任何意义。你绑定事件，它可以在 5 分钟内发生 - 当然脚本不会等到它发生。

我不确定你是如何加载数据的，你只提供了一行：

var state =  Function that executes Tcl script and returns the JSON data

但我很确定 "Function that executes Tcl script" 要么接受回调函数，要么接受 returns thenable/promise 对象。在这种情况下，您的代码应如下所示：

require([
    "dojo/ready", "dojo/_base/window", "dojo/json", "dojo/dom", "dojo/store/Memory",
    "dojo/store/Observable", "dijit/tree/ObjectStoreModel", "dijit/Tree", "dojo/domReady!",
    "dojo/mouse", "dojo/text!./data/all.json"
], function(ready, win, JSON, dom, Memory, Observable, ObjectStoreModel, Tree, mouse, data) {

    $("#getData").click(function() {
        var inputString = "pspTreegetData{}";
        Function_that_executes_Tcl_script(function(data) {
            var testStore = new Memory({
                data: JSON.parse(data) // or if data is Object already just data: data 
            });
        })
    });

});

Answer 2

实际上，您似乎遇到了典型的异步问题...

这样的话听起来更合理...

$("#getData").click(function(){
    var inputString = "pspTreegetData{}";
    var state =  Function that executes Tcl script and returns the JSON data
    var testStore = new Memory({
        data :  JSON.parse(state),
 //...

检查此 post： How do I return the response from an asynchronous call?

为什么 JSON.parse() 不解析这个？

Why won't JSON.parse() parse this?

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