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JavaScript

Posted by kisu kim
kisu kim
11,691 Points

Why can't I use this code instead of the teacher's code? https://teamtreehouse.com/library/the-solution-29

in the video, teacher offered the first answer like this.

https://teamtreehouse.com/library/the-solution-29

teachers.push(...newTeachers);

but Why can I use this code?

teachers.push(newTeachers);

of course, this code doesn't get the right result.

What is the difference between the two? I can't find any lecture about the "..."?

Ryan Martin
Ryan Martin
7,047 Points

Hi Kisu,

Give this documentation a read. The ... is what is called a Spread operator or Rest parameter.

Here is a link to the Treehouse video.

1 Answer

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

The argument "newTeachers" is an array, but the "push" method takes multiple individual arguments. An ellipsis ("...") is the "spread" operator that converts an array into individual arguments.

While not covered in detail in this short workshop, the instructor does give you a short explanation of the operator function in the video. Other courses such as Introducing ES2015 (as suggested by Ryan) cover this operator in detail.

kisu kim
kisu kim
11,691 Points

Thank you for detailed explanation!