Category: Babel unexpected token spread operator

Spread syntax allows an iterable such as an array expression or string to be expanded in places where zero or more arguments for function calls or elements for array literals are expected, or an object expression to be expanded in places where zero or more key-value pairs for object literals are expected. It is common to use Function. Any argument in the argument list can use spread syntax, and the spread syntax can be used multiple times. When calling a constructor with new it's not possible to directly use an array and apply apply does a [[Call]] and not a [[Construct]].

However, an array can be easily used with new thanks to spread syntax:. To use new with an array of parameters without spread syntax, you would have to do it indirectly through partial application:. Without spread syntax, to create a new array using an existing array as one part of it, the array literal syntax is no longer sufficient and imperative code must be used instead using a combination of pushspliceconcatetc.

With spread syntax this becomes much more succinct:. Just like spread for argument lists, Note: Spread syntax effectively goes one level deep while copying an array.

Therefore, it may be unsuitable for copying multidimensional arrays, as the following example shows.

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The same is true with Object. Without spread syntax, this is done as:. Note: Unlike unshiftthis creates a new arr1and does not modify the original arr1 array in-place. It copies own enumerable properties from a provided object onto a new object. Shallow-cloning excluding prototype or merging of objects is now possible using a shorter syntax than Object. Note that Object. Note that you cannot replace or mimic the Object.

In the above example, the spread syntax does not work as one might expect: it spreads an array of arguments into the object literal, due to the rest parameter. Objects themselves are not iterable, but they become iterable when used in an Array, or with iterating functions such as mapreduceand assign. When merging 2 objects together with the spread operator, it is assumed another iterating function is used when the merging occurs.

Spread syntax other than in the case of spread properties can be applied only to iterable objects:. When using spread syntax for function calls, be aware of the possibility of exceeding the JavaScript engine's argument length limit.

See apply for more details. Rest syntax looks exactly like spread syntax, but is used for destructuring arrays and objects.

babel unexpected token spread operator

In a way, rest syntax is the opposite of spread syntax. Spread syntax "expands" an array into its elements, while rest syntax collects multiple elements and "condenses" them into a single element. See rest parameters. Get the latest and greatest from MDN delivered straight to your inbox. Sign in to enjoy the benefits of an MDN account.

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The source for this interactive example is stored in a GitHub repository. The compatibility table on this page is generated from structured data.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project?

Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. What you're trying to do is a stage2 feature. You can either add the plugin as you have done or add the entire stage2 preset. I agree that the documentation is lacking for the Babel plugins, but it's important to realize what is actually supported by ESit seems that is at the root of you confusion. What you're trying to do is an ES7 feature.

In the first link, you can change the ES version at the top, and you may also click on the Babel column to see which features are specifically supported by Babel. I should also add there's no reason you can't use ES7 features. Just be wary of them as their implementation may change.

I tried this :. QuantumInformation - Did you ever get to the bottom of the issue? I'm facing the same problem. In my case I just installed stage-0 and added it on my. Can someone tell me where I'm misunderstanding here?

The es preset page says that this plugin is included by default in its preset.

babel-plugin-transform-object-rest-spread

It's an experimental feature. I mentioned above you need transform-object-rest-spread plugin or stage-2 preset. It's not included in es because it's not in the spec yet and not part of react.

If you use only transform-object-rest-spreadspreads will be transformed, but rests will be left untouched and cause syntax errors. It looks like things have changed once again as preset-stage-2 now have transform-decorators crossed out because of disabled pending proposal update. After many hours searching for info and lots of trial and error, I have tried every combination of plugins and presets possible, yet none of them have worked. Can someone please confirm a set up that works?

I am running Node V6. You'll need babel-plugin-transform-esparameters and babel-plugin-transform-esdestructuring since the plugin relies on them for desctructuring until we are able to make it work standalone or include the other plugins to do so. I have tried with those plugins.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I tried to create a. And my script works when i delete the spread operator. I don't know what doesn't work in this, i read some issues on Github and the setup page on Babel website, but i can't make it work correctly.

That syntax is an experimental proposed syntax for the future, it is not part of es or react so you'll need to enable it.

babel unexpected token spread operator

I had the same issue, installed stage-2 plugin and modified my package. Just as a side note, some text editors in my case Mac Notes will contract Learn more. Asked 4 years, 5 months ago. Active 1 year, 10 months ago.

Viewed 34k times. This is the file where the Unexpected token occurs quite simple. Can anyone show me how to handle this correctly? Thank you.

babel unexpected token spread operator

Bryan Chen Mike Boutin Mike Boutin 4, 10 10 gold badges 30 30 silver badges 57 57 bronze badges. Active Oldest Votes.

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Alternatively: npm install --save-dev babel-preset-stage-3 and use stage-3 in your presets to enable all stage-3 experimental functionality.

MikeBoutin loganfsmyth could you please specify where to specify it as preset? I have the same problem, though I use babelify via cli. Via CLI you need a. Currently its stage 3! Devnegikec Devnegikec 4 4 silver badges 11 11 bronze badges. That's not my text editor. It's just somewhere I occasionally dump blocks of code. That can be really tricky to spot and can cause you problems Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.

Post as a guest Name. Email Required, but never shown. The Overflow Blog.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. Duplicate of We do not support object spread.

I saw on the docs that i can add spread: true but it still gives me the same error. I am using eslint 2. Option you are looking for is experimentalObjectRestSpread. None of these options are working for me, I'm still getting the error, though my eslintrc file relfects all the suggestions recommended here! Source: eslint docs - parser options. AndrewKovalenko did you mean. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Sign up. New issue. Jump to bottom. Unexpected token for spread operator. Labels archived due to age triage. Copy link Quote reply. This comment has been minimized. Sign in to view. Thanks for the repplies, I fixed this bug by instaling babel-eslint.

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Using eslint 3. Tried all the above, still erroring out. DalerAsrorov mentioned this issue Jan 30, Added ESlint task to webpack for demos and added critical rules Sign up for free to subscribe to this conversation on GitHub.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. Closing due to user error.

I had a step after getting source scripts but before applying babel transformations that was relying on es5 code. Might help you find the root cause to your issue:.

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This comment has been minimized. Sign in to view. I am also experiencing this issue after upgrading to Babel 7. Would one of you be able to make a reproducible example? I can take a crack at it this evening. Sign up for free to join this conversation on GitHub. Already have an account?

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setting up the babel plugin for spread operator correctly

Linked pull requests. You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window.Since one of the core tenets of Redux is to never mutate state, you'll often find yourself using Object. For example, in the todoApp below Object. While effective, using Object. An alternative approach is to use the object spread syntax recently added to the JavaScript specification. It lets you use the spread The object spread operator is conceptually similar to the ES6 array spread operator.

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We can simplify the todoApp example above by using the object spread syntax:. The advantage of using the object spread syntax becomes more apparent when you're composing complex objects. Below getAddedIds maps an array of id values to an array of objects with values returned from getProduct and getQuantity.

While the object spread syntax is a Stage 4 proposal for ECMAScript and accepted for the specification release, you will still need to use a transpiler such as Babel to use it in production systems.

In other words, for multidimensional source objects, elements in the copied object at a depth greater than one are mere references to the source object with the exception of primitiveswhich are copied. Thus, you cannot reliably use the Object Spread Operator Using Object Spread Operator Since one of the core tenets of Redux is to never mutate state, you'll often find yourself using Object. Copy return getAddedIds state.Spread syntax allows an iterable such as an array expression or string to be expanded in places where zero or more arguments for function calls or elements for array literals are expected, or an object expression to be expanded in places where zero or more key-value pairs for object literals are expected.

The source for this interactive example is stored in a GitHub repository. It is common to use Function. Any argument in the argument list can use spread syntax, and the spread syntax can be used multiple times. When calling a constructor with new it's not possible to directly use an array and apply apply does a [[Call]] and not a [[Construct]].

However, an array can be easily used with new thanks to spread syntax:. To use new with an array of parameters without spread syntax, you would have to do it indirectly through partial application:. Without spread syntax, to create a new array using an existing array as one part of it, the array literal syntax is no longer sufficient and imperative code must be used instead using a combination of pushspliceconcatetc. With spread syntax this becomes much more succinct:. Just like spread for argument lists, Note: Spread syntax effectively goes one level deep while copying an array.

Therefore, it may be unsuitable for copying multidimensional arrays, as the following example shows. The same is true with Object. Without spread syntax, this is done as:.

Основы ES6 #4: Оператор разворота (spread operator)

Note: Unlike unshiftthis creates a new arr1and does not modify the original arr1 array in-place. It copies own enumerable properties from a provided object onto a new object.

Shallow-cloning excluding prototype or merging of objects is now possible using a shorter syntax than Object. Note that Object. Note that you cannot replace or mimic the Object. In the above example, the spread syntax does not work as one might expect: it spreads an array of arguments into the object literal, due to the rest parameter.

Objects themselves are not iterable, but they become iterable when used in an Array, or with iterating functions such as mapreduceand assign. When merging 2 objects together with the spread operator, it is assumed another iterating function is used when the merging occurs. Spread syntax other than in the case of spread properties can be applied only to iterable objects:. When using spread syntax for function calls, be aware of the possibility of exceeding the JavaScript engine's argument length limit.


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