Gutenberg Block language translation does not work

Question

I have created Gutenberg blocks for my shortcodes, below is some code:

The code in PHP file in init hook to load script:

wp_register_script(
    'my-blocks-script', $pluginurl . '/custom-blocks.js',
    array( 'wp-blocks', 'wp-components', 'wp-element', 'wp-i18n', 'wp-editor' ),
    filemtime( $plugindir . '/custom-blocks.js' )
);

// Script contains translations
if( function_exists('wp_set_script_translations') ) {
    wp_set_script_translations( 'my-blocks-script', 'my-text-domain' );
}

// Shortcode block
register_block_type( 'custom-block/my-shortcode', array(
    'editor_script' => 'my-blocks-script'
) );

JS code: file: custom-blocks.js

( function (blocks, editor, components, i18n, element ) {
    // Define common variables
    var el = wp.element.createElement;
    var registerBlockType = wp.blocks.registerBlockType;
    var InnerBlocks = wp.editor.InnerBlocks;
    var BlockControls = wp.editor.BlockControls;
    var Dashicon = wp.components.Dashicon;
    var __ = wp.i18n.__;

    // Shortcode
    registerBlockType( 'custom-block/my-shortcode', {
        title: __( 'Shortcode Title', 'my-text-domain' ),
        description: '',
        icon: Dashicon.cogs,
        category: 'common',
        attributes: {
            display: {
                type: 'boolean',
                default: true
            }
        },
        edit: function() {
            return [
                el( components.CheckboxControl, {
                    label: __( 'Display it?', 'my-text-domain' ),
                    checked: props.attributes.myAttr,
                    onChange: function( val ) {
                        props.setAttributes({ myAttr: val })
                    }
                } ),
            ];
        },
        save: function(props) {
            return(
                el('div', { className: props.className }, '[my-shortcode display="'+props.attributes.display+'"]' )
            );
        }
    } );

} ) (
    window.wp.blocks,
    window.wp.editor,
    window.wp.components,
    window.wp.i18n,
    window.wp.element
);

Everything works fine, blocks display result too. but now I want to translate "Display it?" text with another language ( I use Loco Translate plugin ), I have checked po file the translation string is there, also translated strings in PHP file works fine.

Here, only the JS file transition does not work.

Answer 1

only the JS file translation does not work

It's most likely because WordPress couldn't find your translation file, which should be in a valid JED format, like so:

{
  "domain": "my-text-domain",
  "locale_data": {
    "my-text-domain": {
      "": {
        "domain":       "my-text-domain",
        "plural-forms": "n != 1",
        "lang":         "en-us"
      },
      "Shortcode Title": [
        "Shortcode Title translated"
      ],
      "Display it?": [
        "Display it? translated"
      ],
      "Another text 1": [
        "Translated text - singular",
        "Translated text - plural"
      ],
      "Another text 2": [
        "Translated text"
        // No plural.
      ]
    }
  }
}

And saved with a name in this format: ${domain}-${locale}-${handle}.json. For example, in your case, it could be my-text-domain-en_US-my-blocks-script.json if the site's language is English (United States) (see "General Settings" → "Site Language").

And when you call wp_set_script_translations(), you can specify the third parameter ($path) which is the full absolute file path to the directory containing the JS/JSON translation files. E.g.:

// $pluginurl was taken from your code
wp_set_script_translations( 'my-blocks-script', 'my-text-domain', $pluginurl . '/languages' );

Also, you can use po2json to convert PO/.po files to a JED-compatible JavaScript object or JSON string.

Notes:

• In the above JS/JSON translation data, the locale as in "lang": "{locale}" should be the GlotPress locale as you can see in the table on this page. For example, en-gb for English (UK).

• In your JS/JSON translation file name, the locale as in ${domain}-${locale}-${handle}.json should be the WP locale as you can see in the table on this page. For example, en_GBfor English (UK).