Category: JavaScript Answers

Sometimes, we want to use dynamic variable string as regex pattern in JavaScript.

In this article, we’ll look at how to use dynamic variable string as regex pattern in JavaScript.

How to use dynamic variable string as regex pattern in JavaScript?

To use dynamic variable string as regex pattern in JavaScript, we can use the RegExp constructor.

For instance, we write

const stringToGoIntoTheRegex = "abc";
const regex = new RegExp("#" + stringToGoIntoTheRegex + "#", "g");

to create a regex object by calling the RegExp constructor with the "#" + stringToGoIntoTheRegex + "#" string.

The 2nd argument is the flag for the regex.

We use 'g' to make the regex return all matches of the pattern.

Conclusion

To use dynamic variable string as regex pattern in JavaScript, we can use the RegExp constructor.

Sometimes, we want to avoid no-param-reassign ESLint error when setting a property on a DOM object with JavaScript.

In thiks article, we’ll look at how to avoid no-param-reassign ESLint error when setting a property on a DOM object with JavaScript.

How to avoid no-param-reassign ESLint error when setting a property on a DOM object with JavaScript?

To avoid no-param-reassign ESLint error when setting a property on a DOM object with JavaScript, we can assign the parameter to a variable.

For instance, we write

const f = (el) => {
  const theElement = el;
  theElement.expand = {};
};

to create the f function.

In it, we assign el to the theElement variable.

And then we add the theElement.expand property to it.

Conclusion

To avoid no-param-reassign ESLint error when setting a property on a DOM object with JavaScript, we can assign the parameter to a variable.

Sometimes, we want to host Material Icons offline with JavaScript.

In this article, we’ll look at how to host Material Icons offline with JavaScript.

How to host Material Icons offline with JavaScript?

To host Material Icons offline with JavaScript, we can install the material-design-icons package.

To install it, we run

npm install material-design-icons --save

Then we import it in our CSS file with

@import '~material-design-icons/iconfont/material-icons.css';

And then we use it by writing

<i class="material-icons">face</i>

in our HTML code.

Conclusion

To host Material Icons offline with JavaScript, we can install the material-design-icons package.

Sometimes, we want to display data values on Chart.js and JavaScript.

In this article, we’ll look at how to display data values on Chart.js and JavaScript.

How to display data values on Chart.js and JavaScript?

To display data values on Chart.js and JavaScript, we add the datalabels.formatter method.

For instance, we write

const myBarChart = new Chart(ctx, {
  type: "bar",
  data: yourDataObject,
  options: {
    // ...
    plugins: {
      datalabels: {
        anchor: "end",
        align: "top",
        formatter(value, context) {
          return getValueFormatted(value);
        },
      },
    },
  },
});

to add the datalabels.formatter method to return the formatted value of the value.

value is the display data value of a point.

Conclusion

To display data values on Chart.js and JavaScript, we add the datalabels.formatter method.

Sometimes, we want to check if character is a letter in JavaScript.

In this article, we’ll look at how to check if character is a letter in JavaScript.

How to check if character is a letter in JavaScript?

To check if character is a letter in JavaScript, we can use a regex.

For instance, we write

const isLetter = (str) => {
  return str.length === 1 && str.match(/[a-z]/i);
};

to create the isLetter function that checks if the str string’s length is 1 and that str matches the /[a-z]/i regex.

[a-z] is the pattern for letters.

And i specifies that we search for matches in a case-insensitive manner.

Conclusion

To check if character is a letter in JavaScript, we can use a regex.