Custom object boolean problem

[TPreece]

Dear Community,

I am currently having an issue with compiling a custom visual. I have intorduced a custom object (myCustomObj) with a boolean property (myprop). I am following the tutorial here: https://blogs.msdn.microsoft.com/tsmatsuz/2016/09/27/power-bi-custom-visuals-programming/

I am getting the error "TYPESCRIPT /src/visual.ts : (44,13) Type 'string | number | boolean | Date | Fill | FillRule | ISemanticFilter | DefaultValueDefinition | I...' is not assignable to type 'boo
lean'.
Type 'string' is not assignable to type 'boolean'." 

I have no idea what the issue could be, it says there is an error with the following line in my update function:

this.myVisualProp = options.dataViews[0].metadata.objects["myCustomObj"]["myprop"];

Yet when I put in a debugger and tried typeof(options.dataViews[0].metadata.objects["myCustomObj"]["myprop"]) in the console it returned "boolean". If I am doing something wrong please let me know, my full code is below: visual.ts, capabilities.json

module powerbi.extensibility.visual {

    export class Visual implements IVisual {
        private target: HTMLElement;
        private myVisualProp: boolean;

        constructor(options: VisualConstructorOptions) {
            var captionArea = document.createElement("div");
            captionArea.innerHTML = "This is a test chart";
            options.element.appendChild(captionArea);
            this.target = document.createElement("div");
            options.element.appendChild(this.target);

            this.myVisualProp = false;
        }

        public update(options: VisualUpdateOptions) {
            this.myVisualProp = options.dataViews[0].metadata.objects["myCustomObj"]["myprop"];
            this.target.innerHTML =
                "Custom Prop is " + this.myVisualProp;
                
        }

        public enumerateObjectInstances(options: EnumerateVisualObjectInstancesOptions): VisualObjectInstanceEnumeration {
            let objectName = options.objectName;
            let objectEnumeration: VisualObjectInstance[] = [];

            switch (objectName) {
                case 'myCustomObj':
                    objectEnumeration.push({
                        objectName: objectName,
                        properties: {
                            myprop: this.myVisualProp,
                        },
                        selector: null
                    });
                    break;
            };

            return objectEnumeration;
        }

        public destroy(): void {
            //TODO: perform any cleanup tasks here 
        }
    }
}

{
    "dataRoles": [
        {
            "displayName": "Category Data",
            "name": "category",
            "kind": "Grouping"
        },
        {
            "displayName": "Measure Data",
            "name": "measure",
            "kind": "Measure"
        },
        {
            "displayName": "Grouping",
            "name": "myGroup",
            "kind": "Grouping"
        }
    ],
    "dataViewMappings": [
        {
            "table": {
                "rows": {
                    "select": [
                        {"for": {"in": "myCategory"}},
                        {"for": {"in": "measure"}}
                    ]
                }
            }
        }
    ],
    "objects": {
    "myCustomObj": {
      "displayName": "Test Object",
      "properties": {
        "myprop": {
          "displayName": "Test Property",
          "type": { "bool": true }
                }
            }
        }
    }
}

[v-chuncz-msft · Accepted solution]

@TPreece,

You may add Type assertions to workaround this issue.