Category: JavaScript

Sometimes, we want to clear this setInterval inside a function with JavaScript.

In this article, we’ll look at how to clear this setInterval inside a function with JavaScript.

How to clear this setInterval inside a function with JavaScript?

To clear this setInterval inside a function with JavaScript, we can call the clearInterval function.

For instance, we write

let intervalListener;
const someProcess = () => {
  //...
  if (stopIntervalIsTrue) {
    window.clearInterval(intervalListener);
  }
};
intervalListener = self.setInterval(someProcess, 1000);

to call setInterval with someProcess to run someProcess every second.

Then if stopIntervalIsTrue is true in someProcess to call window.clearInterval with intervalListener to clear the timer and stop someProcess from running.

Conclusion

To clear this setInterval inside a function with JavaScript, we can call the clearInterval function.

Sometimes, we want to dynamically update values of a Chart.js chart with JavaScript.

In this article, we’ll look at how to dynamically update values of a Chart.js chart with JavaScript.

How to dynamically update values of a Chart.js chart with JavaScript?

To dynamically update values of a Chart.js chart with JavaScript, we set the data set value and update the chart.

For instance, we write

myBarChart.data.datasets[0].bars[2].value = 50;
myBarChart.update();

to set the value we want to update with

myBarChart.data.datasets[0].bars[2].value = 50;

Then we call update to update the chart.

Conclusion

To dynamically update values of a Chart.js chart with JavaScript, we set the data set value and update the chart.

Sometimes, we want to detect if document has loaded with JavaScript.

In this article, we’ll look at how to detect if document has loaded with JavaScript.

How to detect if document has loaded with JavaScript?

To detect if document has loaded with JavaScript, we can check if document.readystate is set to 'complete'.

For instance, we write

if (document.readyState === "complete") {
  init();
}

to check if document.readystate is 'complete'.

If it is, then document has loaded.

Conclusion

To detect if document has loaded with JavaScript, we can check if document.readystate is set to 'complete'.

Sometimes, we want to create a hash or dictionary object in JavaScript.

In this article, we’ll look at how to create a hash or dictionary object in JavaScript.

How to create a hash or dictionary object in JavaScript?

To create a hash or dictionary object in JavaScript, we can create a plain object.

For instance, we write

const a = {};
a["key1"] = "value1";
a["key2"] = "value2";

to create object a.

Then we add properties to it with

a["key1"] = "value1";
a["key2"] = "value2";

The property names are in the square brackets and the values are after the = sign.

Conclusion

To create a hash or dictionary object in JavaScript, we can create a plain object.

Sometimes, we want to add breakpoint on property change with JavaScript.

In this article, we’ll look at how to add breakpoint on property change with JavaScript.

How to add breakpoint on property change with JavaScript?

To add breakpoint on property change with JavaScript, we can define the property with a getter and setter.

Then we add debugger in the setter`.

For instance, we write

const obj = {
  someProp: 10,
};

obj._someProp = obj.someProp;

Object.defineProperty(obj, "someProp", {
  get() {
    return obj._someProp;
  },

  set(value) {
    debugger;
    obj._someProp = value;
  },
});

to call Object.defineProperty to add the someProp property to obj.

We add the getter with get and the setter with set.

We assigned the original someProp property to _someProp and we override the someProp property with the new one we just defined.

debugger is added to set to add a breakpoint when the value changes.

Conclusion

To add breakpoint on property change with JavaScript, we can define the property with a getter and setter.

Then we add debugger in the setter`.