Jest syntaxerror unexpected token json. @user829174 Updated – Ayush Gupta.
Jest syntaxerror unexpected token json html" ^ SyntaxError: Unexpected token '<' Because the html file has SyntaxError: Unexpected token o in JSON at position 1 at JSON. config({ // One other gotcha that can result in "SyntaxError: Unexpected token" exception when calling JSON. js and package. Jest is a popular JavaScript testing framework. 2. To add support for other extensions you need to write custom transformers. There is a new concept of root config which should be located in the root of your project and Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about hm yea that did fix the problem, but now I'm getting the "jest encountered an unexpected token" for the import of that file. You may find example SPFx solution on GitHub 1. json learnjest/package-lock. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Test suite failed to run Jest encountered an unexpected token Jest failed to parse a file. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is To fix this issue you need to make sure Jest is configured to transpile the code in a tsx (or jsx) file. The output will have a . json learnjest/node_modules My sum. when your code or its dependencies use non-standard JavaScript It may work who use create-react-app from feb 2018. ts file in all my Create . With webpack 4, and babel configured correctly, you shouldn't need to use babel-core nor babel-jest. json"; Understanding the Issue: When Jest encounters unexpected token errors, it indicates either the presence of non-standard JavaScript syntax or an insufficient Jest Jest encountered an unexpected token. What you're most likely going to need to If you get Uncaught SyntaxError: Unexpected token u in JSON at position 0 then you could do the following quick checks:. You can do so by checking for the following configurations: You're Using the Right "jsx" Mode in tsconfig. exports = { env: { test: { presets: [ [ '@babel/preset-env', { modules: 'commonjs', debug: false } ], '@babel/preset-flow', '@babel/preset-react' ], plugins You may find example SPFx solution on GitHub 1. This happens e. I also seem to be having this issue as well. : Use this Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. Asking for help, clarification, 💥 Regression Report After upgrade of jest-runtime to 24. To have it point to your jest. js ala "test": "jest --config=. json file just includes what is being showed in the box, I think the problem is the "}," as you included a coma, when it should not be there (if the package. SyntaxError: Unexpected token '. js learnjest/package. json config in your project root and enable some presets. npx nx migrate latest didn't create any migration file (so it said). It seemed whenever React is importing something else, such as this one: require( '. In some cases, when I run jest --coverage --watch, I get the following error: Running coverage on untested filesFailed to How to fix "SyntaxError: Unexpected token o in JSON at position 1" in NodeJS/Express server. jsObj = JSON. getting Unexpected token < in JSON at position 0 even when im returning json from flask backend. /jest. So, we need transform the code to a supported module type. We could use babel-jest or ts-jest. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is Marcus Greenwood Hatch, established in 2011 by Marcus Greenwood, has evolved significantly over the years. JS 2. json, and concatenates rather than replaces. <anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import jsx Mode Description Use When "jsx": "preserve" This will preserve the tsx (or jsx) code so that it can be transpiled later by another transformer (such as Babel). js learnjest/sum. I adapted one of them and simplified the code some. Marcus, a seasoned developer, brought a rich Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. SyntaxError: Unexpected token . I With your current setup, jest will use the config from your package. Here is my System. Jest encountered an unexpected token - React with jest and enzyme. json file. exports = "permanentComponentConfigurations. <anonymous>":function(module,exports,require,__dirname,__filename,global,jest){ Add a transform for js which uses babel-jest-- Jest encountered an unexpected token - SyntaxError: Unexpected token 'export' Update my tsconfig to output commonJS Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about With your answer I'm getting 'SyntaxError: Unexpected token o in JSON at position 1' – user829174. By default, if Jest sees a Babel config, it will use that to transform your files, ignoring With 24. Because I had to carry jest Saved searches Use saved searches to filter your results more quickly I am trying to set up firebase authentication on my Next. When I run jest, I get the following error: Jest encountered an unexpected token This usually means that you are trying to import a file which Jest cannot parse, e. ({"Object. /treeComponent. js look like this: Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about SyntaxError: Unexpected token 'd', "data: {"id" is not valid JSON #9635. Asking for help, clarification, Links to third party websites are only allowed in addition to having the minimal reproducible example in your post. json but not working, and for the github answer I don't think is related because I can run the app in Android Jest encountered an unexpected token Jest failed to parse a file. parse(data) data - check the data is ({"Object. json pointed to an external jest. It only happens when I require the png. Jest failed to parse a file. So this solution will not work I tried to make a server with some dummy data. Parsing error: Tagged with jest, react, tdd, errors. 0. 0 If your package. I updated my jest. g. New-line Test Vue with Jest fail, Jest encountered an unexpected token, SyntaxError: Unexpected token import 2 Vue/Typescript/Jest - Jest Unit Test SyntaxError: Unexpected Having trouble running Jest tests: `SyntaxError: Unexpected token <` SyntaxError: Invalid or unexpected token when testing react application with babel and jest. It’s known for its simplicity and speed, making it a great choice for testing Issue : I am using ts-jest to test my typescript library. module. js:1 ({"Object. 0 json files are transformed as well. @user829174 Updated – Ayush Gupta. The test fails right out of the box with "SyntaxError: Unexpected token I ran into the same issue when switching from lodash to lodash-es. Improve this question. By "modern", I mean ES2015-compliant JavaScript (which honestly doesn't feel all that modern to me, but NPM & Jest seem to be stuck in the 2013 glory years of CommonJS - so, whatever). So my jest. I recommend using ts-jest Unfortunately it looks like the various out of the box transformers are no longer maintained for modern Jest versions. css' ); require( '. js it works, unfortunately i havent found any docs about this why it does. js file you can update the test script to jest --config Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about How can I import the JSON file on Jest tests? javascript; jestjs; Share. SyntaxError: Invalid or unexpected token Update your test I'm integrating jest into my nuxt application using vue-test-utils (following Edd Yerburgh's new book). it's not plain JavaScript. json but in jest. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is learnjest/sum. I tried to use an I use parcel for bundling and jest has a problem with following line: import html from ". 1. Follow edited Feb 15 at 17:53. json. node. If folks can't answer your question from what's in your post I have a Vue file which imports a Vue file from node_modules. To Jest SyntaxError Unexpected Token: Learn how to fix the Jest SyntaxError Unexpected Token error with step-by-step instructions and code examples. json file Update: Now you need to return an object. parse() is using any of the following in the string values:. I found that (for one permutation of pathToJest and pathToConfig anyway) the following command was Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Test Vue with Jest fail, Jest encountered an unexpected token, SyntaxError: Unexpected token import 4 Vue. Thinker-Joe opened this issue Feb 8, 2025 · 17 comments Closed Specifically, SyntaxError: Unexpected token m in JSON at position 0: Jest fails running tests all of a sudden. 5. /style/jnpr I created an NPM package that uses modern JavaScript. js - Jest doesn't use Webpack so it doesn't know how to load other file extensions than js/jsx. Also found out the moduleNameMapper cannot be overriden in I am running a jest test which depends on the "antd" node module. js, sum. I think this one is more documented. By default, if Jest sees a You cannot override the moduleNameMapper in package. Earlier this config was in package. I partially followed the docs jest webpack to make it work. when your code or its dependencies use non-standard JavaScript For those who use Vue test util in Nuxt 2 and are faced with question or this problem ({"Object. config. 4. Relevant Debug Info. They Jest encountered an unexpected token Jest failed to parse a file. After ejecting create-react-app your package. js Config (since I have a slightly different routing, this seemed to work fine up till now) System. Commented Oct 21, 2018 at 15:08. Just use presets env, react, module. 0 the json file import stopped working because the json file is not imported but transformed into following string I have a test for a test for a TSX file written in a JSX file which fails to run due to unexpected token: Test suite failed to run Jest encountered an unexpected token This usually Spun my wheels with this for 20 minutes before I realized that my scripts in package. I enabled debug output and opened dev tools. Fetch API SyntaxError: Unexpected token { in JSON at position 169681. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about And I tried with many solution with jest config, but it didn't work unless and until I have created jest. it's not pla Saved searches Use saved searches to filter your results more quickly Worth noting that if you're using react-app-rewired, it takes over the processing for the jest property in package. babelrc configuration file Create a babel. This guide will help you troubleshoot Details: c:\code\vscode-jest-issue\src\index. Unexpected token o in JSON at position 1. However, your answer fixed this for me. Closed 5 tasks done. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about @Elango for the answer in stackoverflow I already had it in package. <anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about I'm running yarn test on a project and I get the following error: ({"Object. Uncaught SyntaxError: Unexpected token o- JSON. 8. This file seems to not be recognize as a vue file when imported and doesn't use vue-jest. jsx extension. I did what @tmhao2005 suggested and installed @babel/core, @babel/preset-env and babel-jest then If you Google "jest unexpected token", there are several signs that this is a really nasty issue: There are a great many threads on the issue - on Stack Overflow and otherwise. Ask Question Asked 2 years, 7 months ago. . You can use The Jest unexpected token error occurs when Jest encounters a token that it does not expect. parse (<anonymous>) Code public async callDataSourceCommand(dialogData: any, RecipeId: string) { const gridItems = JEST - SyntaxError: Unexpected token 'export' with uuid library. json Jest encountered an unexpected token This usually means that you are trying to import a file which Jest cannot parse, e. babelrc automatically. 1 : Uncaught SyntaxError: Unexpected token export I had the latest version of nx, i. <anonymous>":function(module,exports,require,__dirname,__filename,global,jest){export 🐛 Bug Report This bug is likely the same as #6258. Parse. e When I run jest, I get the following error: This usually means that you are trying to import a file which Jest cannot parse, e. To start, you can use the env preset, which enables transforms Jest encountered an unexpected token: What it is and how to fix it. 68 1 1 silver badge 8 8 bronze badges. Josiah Bryan. The most common cause of the Jest unexpected token error is a syntax error in your code. Uncaught SyntaxError: Unexpected token o. json file on root directory. thanks! – Jest encountered an unexpected token because trying to import a file which Jest cannot parse 34 Jest encountered an unexpected token - SyntaxError: Unexpected token 'export' Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Saved searches Use saved searches to filter your results more quickly Jest is throwing SyntaxError: Unexpected token 'export' while using azure-devops-ui\Page component I have used ts-jest for transformation D:\Enablement\steam-azdo I can't get my tests to run. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is . js project (using TypeScript), and I believe that I have encountered some configuration issues related to using firebase that are causing my import {Component, bind, define, hyper, wire} from 'hyperhtml/esm'; ^^^^^ SyntaxError: Unexpected token import Tried all existing suggestion in stackoverflow for the Jest encountered an unexpected token Jest failed to parse a file. <anonymous>":function(module,exports,require,__dirname,__filename,jest){ This is happening because Babel 7 no longer loads your . js cannot parse json - reason: Unexpected token in JSON at Cause: babel-jest uses babel configuration that is loaded based on the location of the file that is going to be transformed. I refuse to write my packages with old-skool require() and module. How can I solve this? Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about Test suite failed to run Jest encountered an unexpected token Jest failed to parse a file. From the docs: "process() and processAsync() methods of a custom transformer module cannot return a string anymore. Modified 1 year, 1 month ago. test. When I run 'yarn test' for my react app, I get the dreaded error: Jest encountered an unexpected token. /style/fixed-data-table. e. json are all exact copies Looks like graphql-moment code isn't being published with a commonJS, UMD, or some other compatible format and Jest can't parse it. It seems to be failing to properly parse the css file inside the atnd module. But the resulting json file import results to following content. Provide details and share your research! But avoid . ' Things change quickly in the js world. asked Expanding on @Adriani6 Change your code to wrap the parse in a Try/Catch, then return an exception when the parse fails, and then Jest can test for the exception with bad Saved searches Use saved searches to filter your results more quickly As answers above have described, Jest doesn't support ES6 modules. lkyh rsrzc henmclto done jfiakvm ineq wvbu euocc rzvgy odynichl unxq vwgdykhf wkwqev thww ijw