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Author's profile photo Yunus Tuzun

UI5 Custom Task Creation and Usage


In UI5 tooling, a custom task can be used to include various operations during the build phase. As a simple demo, I will explain how we will remove the i18n texts that are not used in the project. This custom task will save time when you combine your project files from different workspaces and make your i18n texts redundant.

Prepare task configuration

In the ui5.yaml file, we need to specify which task file to run and reference other tasks to which runtime to consider. In this example, our custom task will run before the standard task replaceCopyright.
    - name: cleanUnusedi18nKeys
      beforeTask: replaceCopyright
# Task extension as part of your project
specVersion: "2.1"
kind: extension
type: task
  name: cleanUnusedi18nKeys
  path: tasks/cleanUnusedi18nKeys.js

Prepare task file

It is necessary to export a function in the following structure to the file to callback a continuous operation. The workspace object allows us to perform the desired operations on the files.

module.exports = async function ({ workspace, dependencies, taskUtil, options }) { 


Our I18n keyword is searched for in the project files (controller, fragment, views). If it is not found, it is not inserted as a string in the new i18n file. All asynchronous functions are used with await keywords to continue with the synchronous process.

   const textResources = await workspace.byGlob("**/*{view.xml,fragment.xml,controller.js,manifest.json}");
    const i18nFiles = await workspace.byGlob("**/*.properties");
    await Promise.all( (i18nFile) => {
        lines = lines.filter((l) => l.found === true);

        for (let i = 0; i < lines.length; i++) {
            line = lines[i];
            i18nString += line.key + " = " + line.value + "\n";
        i18nString.substring(0, i18nString.length - 2);

        await i18nFile.setString(i18nString)

        await workspace.write(i18nFile).then(() => console.log('DONE'));


With the ui5 build command, the i18n keys that were not used in the workspace were deleted during the build phase. Unused i18n texts will not exist anymore.

Final words

I have uploaded the repository code to Github for you to use as a reference when building your custom task. The API reference is provided for you to extend your requirements. Additionally, various libraries like Babel, Grunt.js can be used while performing these operations.

Custom tasks in UI5 Tooling allow us to perform file formatting, transpile, linting, and other operations before or during the build phase. Thanks to contributors in the UI5 Ecosystem , we have many different out-of-box tasks that meet many requirements.


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      Author's profile photo Ajaroddin Havaldar
      Ajaroddin Havaldar

      Hello Yunus,

      Thank you for this well explained blog.

      Just one doubt where we need to put our task files? I mean it should be outside webapp or we can create tasks folder in webapp folder?


      And also can we create custom task to update application version in manifest.json file?


      Best Regards,