Ember CLI / Ember.js中的承諾

Question

我正在嘗試編寫ember-cli-deploy插件，並且確實可以在Promise中使用一些幫助。 在主插件的index.js中，我有以下代碼index.js：

prepare: function(context) {
    ...
    ...
    var awsDeploymentOptions = {....};
    this._awsCodeDeployClient = new CodeDeployClient({awsDeploymentOptions: awsDeploymentOptions});

}
upload: function() {
    ...
    ...
    var uploadPromise = (awsDeploymentOptions.revision.revisionType === 'S3') ? this._awsS3Client.upload(filesToUpload, this.readConfig('s3UploadOptions')) : new Promise().resolve();
    return uploadPromise.then(function(result){return this._awsCodeDeployClient.createDeployment(result)}.bind(this));
}

以上工作按預期進行，並且諾言得到了正確解決。

如果我將上面的代碼更改為：

return uploadPromise.then(this._awsCodeDeployClient.createDeployment);

代碼失敗。 然后，我嘗試了以下操作，但同樣失敗了：

return uploadPromise.then(this._awsCodeDeployClient.createDeployment.bind(this));

在以上兩種情況下，它都會在createDeployment方法中抱怨未定義的變量/屬性，其定義如下：

createDeployment: function(s3FileUploadOptions) {
    return new Promise(function(resolve, reject) {
        //This is where the problem lies. this is never resolved
        //to this module's 'this' and I cannot access this.deploymentOptions
        //Any reference to 'this' variable causes an error
        var awsDeploymentOptions = this.awsDeploymentOptions;
        this.codeDeploy.createDeployment(this.awsDeploymentOptions, function(error, data) {
            if (error)
                reject(error); // an error occurred
            else resolve({awsDeploymentId:data.deploymentId}); // successful response. Return deployment Id
        }.bind(this));
    }.bind(this));
}

在上述兩種情況下，我在做什么錯？

Answer 1

這個怎么樣？

return uploadPromise.then(result => this._awsCodeDeployClient.createDeployment(result));

箭頭函數使作用域不受調用上下文的影響。