如何在JavaScript中跨多个函数使用全局变量

How can I use Global variable across multiple functions in JavaScript?

本文关键字：函数 全局变量 JavaScript      更新时间：2023-11-21

我有一段代码，用于检查使用的权限级别和组成员身份，并在用户具有访问网站该部分的正确权限时启动对话框。

function bindSettingsButton() {
            $("#mt-ngw-personalsettings").on("click", function() {
                RequestNewSite();
            });
        }
        function RequestNewSite()   {
            var HasPermission = false;
            var isGroupMember = false;
            CheckCurrentUserMembership();
            CheckUserHasEditPermissions();
            CheckUserPermissions();
        }
        function CheckCurrentUserMembership() {
            var clientContext = new SP.ClientContext.get_current();
            this.currentUser = clientContext.get_web().get_currentUser();
            clientContext.load(this.currentUser);
            this.userGroups = this.currentUser.get_groups();
            clientContext.load(this.userGroups);
            clientContext.executeQueryAsync(OnQuerySucceeded, OnQueryFailed);
        }
        function OnQuerySucceeded() {
            var isMember = false;
            var groupsEnumerator = userGroups.getEnumerator();
            while (groupsEnumerator.moveNext()) {
                var group = groupsEnumerator.get_current();
                if(group.get_title() == "Create Site OptOut") {
                isMember = true;
                this.isGroupMember = true;
                break;
                }
            }
        }
        function OnQueryFailed() 
        {
            alert("Couldn't check user group membership. Please contact  to resolve this issue.");
        }
        function CheckUserHasEditPermissions()  {
            context = new SP.ClientContext.get_current();
            web = context.get_web();
            this._currentUser = web.get_currentUser();
            this._theList = web.get_lists().getByTitle('siterequests');
            context.load(this._currentUser);
            context.load(this._theList, 'EffectiveBasePermissions')
            context.executeQueryAsync(Function.createDelegate(this, this.onPermissionsSuccessMethod), Function.createDelegate(this, this.onPermissionsFailureMethod));
        }
        function onPermissionsSuccessMethod(sender, args)   {
            if (this._theList.get_effectiveBasePermissions().has(SP.PermissionKind.editListItems))
            {
                this.HasPermission = true;
            }
            else
            {
                this.HasPermission = false;
            }
        }
        function onPermissionsFailureMethod()
            {
                alert("Couldn't check permissions. Please contact  to resolve this issue.");
            }
        function CheckUserPermissions() {
            if(this.isGroupMember == true)
            {
                alert("You do not have permission to create sites. If you believe you should have access to this functionality, please contact .");
            }
            else if(this.HasPermission == false)
            {
                alert("You do not have permission to create sites. If you believe you should have access to this functionality, please contact .");
            }
            else
            {
                showDialogue();
                document.getElementById("next-stage").focus();
            }
        }

不幸的是，当它到达本节末尾时，变量HasPermission和isGroupMember仍然未定义，因此对话会自动为每个用户启动。我有一种感觉，我滥用了.this关键字，这是一个范围错误，但我在JS方面不够专业，无法确定或修复它。有人能告诉我到底做错了什么以及如何修复它吗？

您正在执行异步函数，这意味着即使您首先启动的东西还没有完成，其余的代码也将继续执行。在onPermissionsSuccessMethod和OnQuerySucceeded函数完成后，您必须调用CheckUserPermissions。

除此之外，HasPermission和isGroupMember变量是RequestNewSite函数的本地变量，这意味着它们不在CheckUserPermissions函数的范围内。

    var HasPermission = false;
    var isGroupMember = false;
    var CompletedCallbacks = 0;
    function bindSettingsButton() {
        $("#mt-ngw-personalsettings").on("click", function() {
            RequestNewSite();
        });
    }
    function RequestNewSite()   {
        CheckCurrentUserMembership();
        CheckUserHasEditPermissions();
    }
    function CheckCurrentUserMembership() {
        var clientContext = new SP.ClientContext.get_current();
        this.currentUser = clientContext.get_web().get_currentUser();
        clientContext.load(this.currentUser);
        this.userGroups = this.currentUser.get_groups();
        clientContext.load(this.userGroups);
        clientContext.executeQueryAsync(OnQuerySucceeded, OnQueryFailed);
    }
    function OnQuerySucceeded() {
        var isMember = false;
        var groupsEnumerator = userGroups.getEnumerator();
        while (groupsEnumerator.moveNext()) {
            var group = groupsEnumerator.get_current();
            if(group.get_title() == "Create Site OptOut") {
            isMember = true;
            isGroupMember = true;
            break;
            }
        }
        CompletedCallbacks++;
        CheckUserPermissions();
    }
    function OnQueryFailed() 
    {
        alert("Couldn't check user group membership. Please contact SPCOE@capita.co.uk to resolve this issue.");
    }
    function CheckUserHasEditPermissions()  {
        context = new SP.ClientContext.get_current();
        web = context.get_web();
        this._currentUser = web.get_currentUser();
        this._theList = web.get_lists().getByTitle('siterequests');
        context.load(this._currentUser);
        context.load(this._theList, 'EffectiveBasePermissions')
        context.executeQueryAsync(Function.createDelegate(this, this.onPermissionsSuccessMethod), Function.createDelegate(this, this.onPermissionsFailureMethod));
    }
    function onPermissionsSuccessMethod(sender, args)   {
        if (this._theList.get_effectiveBasePermissions().has(SP.PermissionKind.editListItems))
        {
            HasPermission = true;
        }
        else
        {
            HasPermission = false;
        }
        CompletedCallbacks++;
        CheckUserPermissions();
    }
    function onPermissionsFailureMethod()
        {
            alert("Couldn't check permissions. Please contact SPCOE@capita.co.uk to resolve this issue.");
        }
    function CheckUserPermissions() {
        if(CompletedCallbacks != 2) return;
        if(isGroupMember == true)
        {
            alert("You do not have permission to create sites. If you believe you should have access to this functionality, please contact SPOCOE@capita.co.uk.");
        }
        else if(HasPermission == false)
        {
            alert("You do not have permission to create sites. If you believe you should have access to this functionality, please contact SPOCOE@capita.co.uk.");
        }
        else
        {
            showDialogue();
            document.getElementById("next-stage").focus();
        }
    }

这个代码应该可以工作。

$("#mt-ngw-personalsettings").on("click", function() {
  RequestNewSite();
});

如果您希望使用RequestNewSite作为构造函数，则需要使用new来分配它。如果您作为函数调用，则不会创建对象（因此也不会创建状态）。

此外，该类型的所有成员都需要在this上显式创建。

所以

function RequestNewSite()   {
  var HasPermission = false;
    var isGroupMember = false;
    CheckCurrentUserMembership();
    CheckUserHasEditPermissions();
    [...]

需要

function RequestNewSite()   {
  this.HasPermission = false;
  this.isGroupMember = false;
  this.CheckCurrentUserMembership();
  this.CheckUserHasEditPermissions();
  [...]
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