Author: John Au-Yeung

Sometimes, we want to fix Syntax error: Illegal return statement in JavaScript.

In this article, we’ll look at how to fix Syntax error: Illegal return statement in JavaScript.

How to fix Syntax error: Illegal return statement in JavaScript?

To fix Syntax error: Illegal return statement in JavaScript, we should use return only in functions.

For instance, we write

const myFunction = () => {
  //...
  return myThing;
};

to define the myFunction function.

And in it, we return the myThing variable.

Conclusion

To fix Syntax error: Illegal return statement in JavaScript, we should use return only in functions.

Sometimes, we want to get the current minute, hour, day, week, month, year of a given millisecond time with JavaScript.

In this article, we’ll look at how to get the current minute, hour, day, week, month, year of a given millisecond time with JavaScript.

How to get the current minute, hour, day, week, month, year of a given millisecond time with JavaScript?

To get the current minute, hour, day, week, month, year of a given millisecond time with JavaScript, we can use various date methods.

For instance, we write

const date = new Date();

const seconds = date.getSeconds();
const minutes = date.getMinutes();
const hour = date.getHours();

const year = date.getFullYear();
const month = date.getMonth();
const day = date.getDate();

const dayOfWeek = date.getDay();
const milliSeconds = date.getMilliseconds();

to get various parts of the date.

getSeconds gets the seconds of the minute.

getMinutes gets the minutes of the hour.

getHours gets the hours of the day.

getFullYear gets the 4 digit year.

getMonth gets the month of the date. 0 is January, 1 is February, etc.

getDay gets the day of the month.

getMilliseconds gets the number of milliseconds of the second.

Conclusion

To get the current minute, hour, day, week, month, year of a given millisecond time with JavaScript, we can use various date methods.

Sometimes, we want to create File object from Blob with JavaScript.

In this article, we’ll look at how to create File object from Blob with JavaScript.

How to create File object from Blob with JavaScript?

To create File object from Blob with JavaScript, we can use the File constructor`.

For instance, we write

const file = new File([blob], "filename");

to create a File object from a blob by putting it in an array.

The 2nd argument is a string with the file’s name.

Conclusion

To create File object from Blob with JavaScript, we can use the File constructor`.

Sometimes, we want to fix Cannot read property ‘push’ of undefined when combining arrays with JavaScript.

In this article, we’ll look at how to fix Cannot read property ‘push’ of undefined when combining arrays with JavaScript.

How to fix Cannot read property ‘push’ of undefined when combining arrays with JavaScript?

To fix Cannot read property ‘push’ of undefined when combining arrays with JavaScript, we should make sure we’re calling push on an array.

For instance, we write

const order = new Array();
order.push(a[n]);

to call order.push to append a new entry into the order array.

Conclusion

To fix Cannot read property ‘push’ of undefined when combining arrays with JavaScript, we should make sure we’re calling push on an array.

Sometimes, we want to change the key name in an array of objects with JavaScript.

In this article, we’ll look at how to change the key name in an array of objects with JavaScript.

How to change the key name in an array of objects with JavaScript?

To change the key name in an array of objects with JavaScript, we use the array map method.

For instance, we write

const arrayOfObj = [
  {
    key1: "value1",
    key2: "value2",
  },
  {
    key1: "value1",
    key2: "value2",
  },
];
const newArrayOfObj = arrayOfObj.map(({ key1: stroke, ...rest }) => ({
  stroke,
  ...rest,
}));

console.log(newArrayOfObj);

to call arrayOfObj.map with a function that destructures the object we’re iterating through.

Then we return a new object that has the stroke property and the rest object’s properties spread into the returned object.

rest is an object with properties other than key1.

We rename key1 to stroke when we’re destructuring.

Conclusion

To change the key name in an array of objects with JavaScript, we use the array map method.