Can U Use Continue in a Foreach
There is no way to stop or break a forEach() loop other than by throwing an exception in JavaScript. Use a simple loop instead.
Simple example code interrupts execution you would have to throw an exception of some sort.
<!DOCTYPE html> <html> <head> <script> var BreakException = {}; let arr = [1, 2, 3]; try { arr.forEach(function(el) { console.log(el); if (el === 2) throw BreakException; }); } catch (e) { console.log("BreakException") if (e !== BreakException) throw e; } </script> </head> <body> </body> </html> Output:
JavaScript exceptions aren't terribly pretty. A traditional for loop might be more appropriate if you really need to break inside it.
Use Array#some
Instead, use Array#some:
[1, 2, 3].some(function(el) { console.log(el); return el === 2; }); This works because some returns true as soon as any of the callbacks, executed in array order, return true, short-circuiting the execution of the rest.
Source: stackoverflow.com
Do comment if you have any doubts or suggestions on this JS forEach topic.
Note: The All JS Examples codesare tested on the Firefox browser and the Chrome browser.
OS:Windows 10
Code: HTML 5 Version
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The break statement "jumps out" of a loop.
The continue statement "jumps over" one iteration in the loop.
The Break Statement
You have already seen the break statement used in an earlier chapter of this tutorial. It was used to "jump out" of a switch() statement.
The break statement can also be used to jump out of a loop:
Example
for (let i = 0; i < 10; i++) {
if (i === 3) { break; }
text += "The number is " + i + "<br>";
}
Try it Yourself »
In the example above, the break statement ends the loop ("breaks" the loop) when the loop counter (i) is 3.
The Continue Statement
The continue statement breaks one iteration (in the loop), if a specified condition occurs, and continues with the next iteration in the loop.
This example skips the value of 3:
Example
for (let i = 0; i < 10; i++) {
if (i === 3) { continue; }
text += "The number is " + i + "<br>";
}
Try it Yourself »
JavaScript Labels
To label JavaScript statements you precede the statements with a label name and a colon:
The break and the continue statements are the only JavaScript statements that can "jump out of" a code block.
Syntax:
break labelname;
continue labelname;
The continue statement (with or without a label reference) can only be used to skip one loop iteration.
The break statement, without a label reference, can only be used to jump out of a loop or a switch.
With a label reference, the break statement can be used to jump out of any code block:
Example
const cars = ["BMW", "Volvo", "Saab", "Ford"];
list: {
text += cars[0] + "<br>";
text += cars[1] + "<br>";
break list;
text += cars[2] + "<br>";
text += cars[3] + "<br>";
}
Try it Yourself »
A code block is a block of code between { and }.
Test Yourself With Exercises
Exercise:
Make the loop stop when i is 5.
for (i = 0; i < 10; i++) { console.log(i); if (i == 5) { ; } } Start the Exercise
It goes without saying that the majority of coding is dealing with loops. There are all kinds of loops with all sorts of different syntaxes. It's challenging to make sense of it all, but part of becoming proficient in programming is knowing what syntax to use, especially when there are multiple options. One loop in javascript is the forEach loop. It's used to iterate over arrays. It provides a nice syntax, but issues arise when we try to get a bit more complicated, such as breaking out of the loop. Let's learn how to exit a forEach loop in javascript.
How to Exit a forEach Loop in Javascript
Officially, there is no proper way to break out of a forEach loop in javascript. Using the familiar break syntax will throw an error. If breaking the loop is something you really need, it would be best to consider using a traditional loop.
Let's look at the following code snippet.
let data = [ {name: 'Rick'},{name: 'Steph'},{name: 'Bob'} ] data.forEach(obj => { console.log(obj.name) if (obj.name === 'Steph') { break; } }) You would expect the code to stop executing after it finds the name "Steph"; however, it throws anUnsyntactic break error.
Solution
As in most things in programming, there is, of course, a workaround. We can throw and catch an exception while iterating our array. Let's take a look at how we could achieve this.
let data = [ {name: 'Rick'},{name: 'Steph'},{name: 'Bob'} ] try { data.forEach(obj => { console.log(obj.name) if (obj.name === 'Steph') { throw 'Break'; } }) } catch (e) { if (e !== 'Break') throw e } As you can see here, we wrapped our forEach statement in atry catch block. Where we would typically do abreak, we perform a "throw 'Break'"
We then jump down to our catch and check what our error is. If it's anything other than "Break", we throw it up the error chain. Otherwise, we continue with our code execution.
Although this solution works, it's not very clean. Let's take a look at a few better alternatives.
Alternative #1: for…of loop (Preferred)
The for…of loop would be the preferred solution to this problem. It provides clean easy to read syntax and also lets us usebreak once again.
let data = [ {name: 'Rick'},{name: 'Steph'},{name: 'Bob'} ] for (let obj of data) { console.log(obj.name) if (obj.name === 'Steph') break; } Another added benefit of using the for…of loop is the ability to performawait operations within it. We would not be able to use the await syntax within a forEach loop.
Alternative #2: every
We can also use the "every" array prototype. Let's take a look at that code snippet.
let data = [ {name: 'Rick'},{name: 'Steph'},{name: 'Bob'} ] data.every(obj => { console.log(obj.name) return !(obj.name === 'Steph') }) Theevery prototype will test each element against our function and expect aboolean return. When a value is returned false, the loop will be broken. In this case, we inverse our name test and return false when the name is equal to "Steph", the loop breaks, and we continue our code.
Alternative #3: some
Very similar to theevery prototype, we could also use the "some" array prototype. Thesomeprototype is almost identical to the every prototype. The only difference is that a true return will break the loop. Let's take a look at the code.
let data = [ {name: 'Rick'},{name: 'Steph'},{name: 'Bob'} ] data.some(obj => { console.log(obj.name) return (obj.name === 'Steph') }) You can see that the function returns true when it reaches the "Steph" name and breaks the loop. Whether you choosesome orevery is entirely dependent on what you believe to be the most readable.
You now know how to exit a forEach loop in Javascript. You have multiple alternative solutions and also the primary workaround. Choose the option that fits your use case the best. Remember, code readability is very important, so choose wisely. Happy Coding!
Can we use continue and break statements with the forEach loop?
In Kotlin, we cannot explicitly use break and continue statements explicitly inside a forEach loop, but we can simulate the same action.
Does Break stop forEach?
break ends execution of the current for , foreach , while , do-while or switch structure.
Can we use break and continue in JavaScript?
JavaScript Labels continue labelname; The continue statement (with or without a label reference) can only be used to skip one loop iteration. The break statement, without a label reference, can only be used to jump out of a loop or a switch.
How do you continue in a forEach?
Use return For practical purposes, return in a forEach() callback is equivalent to continue in a conventional for loop. When you return , you skip the rest of the forEach() callback and JavaScript goes on to the next iteration of the loop.
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Source: https://kafesentul.com/can-we-use-break-and-continue-in-foreach-loop-in-javascript
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