javascript - 为什么Javascript对象点表示法会导致错误？

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我已经阅读了很多有关Java中点表示法和方括号表示法之间差异的信息。我的理解如下。

点表示法：


属性标识只能是字母数字（和_和$）
属性标识符不能以数字开头。
属性标识符不能包含变量。
确定-obj.prop_1，obj.prop $
不正常-obj.1prop，obj.prop名称


括号符号：


属性标识符必须是字符串或引用字符串的变量。
可以使用以数字开头的变量，空格和字符串
OK — obj [“ 1prop”]，obj [“ prop name”]


因此，我仍然不明白为什么在以下示例中，如果使用点符号而不是方括号符号，棉绒会引发错误。

    this.contactConfig = {
        "prop": "addresses",
        groups: [
            {
                "label": "Physical Address",
                "type": "address",
                "prop": 'physical_address',
                "controls": [
                    {
                        "label": "Address Line 1",
                        "prop": "address1"
                    },
                    {
                        "label": "Address Line 2",
                        "prop": "address2"

                    },
                    {
                        "label": "City",
                        "prop": "city"

                    },
                    {
                        "label": "State",
                        "prop": "state",
                        "type": "dropdown"

                    },
                    {
                        "label": "Zip Code",
                        "prop": "zipcode"
                    }
                ]
            },
            {
                "label": "Mailing Address",
                "type": "address",
                "prop": "mailling_address",
                "same": false,
                "controls": [
                    {
                        "label": "Address Line 1",
                        "prop": "mailing_address1"

                    },
                    {
                        "label": "Address Line 2",
                        "prop": "mailing_address2"

                    },
                    {
                        "label": "City",
                        "prop": "mailing_city"
                    },
                    {
                        "label": "State",
                        "prop": "mailing_state",
                        "type": "dropdown"
                    },
                    {
                        "label": "Zip Code",
                        "prop": "mailing_zipcode"
                    }
                ]
            },
            {
                "label": "Contact",
                "prop": "contact",
                "controls": [
                    {
                        "label": "Email",
                        "prop": "email"
                    },
                    {
                        "label": "Primary Phone Number",
                        "prop": "primary_phone_number"
                    },
                    {
                        "label": "Secondary Phone Number",
                        "prop": "secondary_phone_number"
                    }
                ]
            }
        ]
    }

    this.profileForm = new FormGroup({});
    this.contactConfig["groups"].forEach(group => {
        console.log('group', group)
        group.controls.forEach(control => {
            this.formControlService.addFormGroupToFormGroup(this.profileForm, group);
        })
    })

如果使用点表示法，我的短毛绒会引发以下错误：Property 'groups' does not exist on type '{}'.

如果我更改代码以使"groups" groups仍然出现相同的错误。有什么想法为什么我必须使用方括号表示法？

TSLint错误。

最佳答案

您可以将其与方括号符号一起使用。您只是有一个语法错误：

this.contactConfig['groups]'

应该：

this.contactConfig['groups']

this.contactConfig = {
        prop: "addresses",
        groups: [
            {
                label: "Physical Address",
                type: "address",
                prop: 'physical_address',
                controls: [
                    {
                        label: "Address Line 1",
                        prop: "address1"
                    },
                    {
                        label: "Address Line 2",
                        prop: "address2"

                    },
                    {
                        label: "City",
                        prop: "city"

                    },
                    {
                        label: "State",
                        prop: "state",
                        type: "dropdown"

                    },
                    {
                        label: "Zip Code",
                        prop: "zipcode"
                    }
                ]
            },
            {
                label: "Mailing Address",
                type: "address",
                prop: "mailling_address",
                same: false,
                controls: [
                    {
                        label: "Address Line 1",
                        prop: "mailing_address1"

                    },
                    {
                        label: "Address Line 2",
                        prop: "mailing_address2"

                    },
                    {
                        label: "City",
                        prop: "mailing_city"
                    },
                    {
                        label: "State",
                        prop: "mailing_state",
                        type: "dropdown"
                    },
                    {
                        label: "Zip Code",
                        prop: "mailing_zipcode"
                    }
                ]
            },
            {
                label: "Contact",
                prop: "contact",
                controls: [
                    {
                        label: "Email",
                        prop: "email"
                    },
                    {
                        label: "Primary Phone Number",
                        prop: "primary_phone_number"
                    },
                    {
                        label: "Secondary Phone Number",
                        prop: "secondary_phone_number"
                    }
                ]
            }
        ]
    };

    this.contactConfig['groups'].forEach(group => {
        console.log('group', group);
        group.controls.forEach(control => {
            this.formControlService.addFormGroupToFormGroup(this.profileForm, group);
        });
    });

您也可以使用点表示法：

this.contactConfig = {
        prop: "addresses",
        groups: [
            {
                label: "Physical Address",
                type: "address",
                prop: 'physical_address',
                controls: [
                    {
                        label: "Address Line 1",
                        prop: "address1"
                    },
                    {
                        label: "Address Line 2",
                        prop: "address2"

                    },
                    {
                        label: "City",
                        prop: "city"

                    },
                    {
                        label: "State",
                        prop: "state",
                        type: "dropdown"

                    },
                    {
                        label: "Zip Code",
                        prop: "zipcode"
                    }
                ]
            },
            {
                label: "Mailing Address",
                type: "address",
                prop: "mailling_address",
                same: false,
                controls: [
                    {
                        label: "Address Line 1",
                        prop: "mailing_address1"

                    },
                    {
                        label: "Address Line 2",
                        prop: "mailing_address2"

                    },
                    {
                        label: "City",
                        prop: "mailing_city"
                    },
                    {
                        label: "State",
                        prop: "mailing_state",
                        type: "dropdown"
                    },
                    {
                        label: "Zip Code",
                        prop: "mailing_zipcode"
                    }
                ]
            },
            {
                label: "Contact",
                prop: "contact",
                controls: [
                    {
                        label: "Email",
                        prop: "email"
                    },
                    {
                        label: "Primary Phone Number",
                        prop: "primary_phone_number"
                    },
                    {
                        label: "Secondary Phone Number",
                        prop: "secondary_phone_number"
                    }
                ]
            }
        ]
    };

    this.contactConfig.groups.forEach(group => {
        console.log('group', group);
        group.controls.forEach(control => {
            this.formControlService.addFormGroupToFormGroup(this.profileForm, group);
        });
    });

另外（FYI），使用对象文字，除非您尝试创建JSON字符串，否则无需引用您的对象键/属性名称。最后，不依赖自动分号插入，而是自己输入分号是一个非常好的主意。

关于javascript - 为什么Javascript对象点表示法会导致错误？ ，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/57366863/