Example: Dynamic handler for multi-enum fields

See the dynamic handler documentation.

In this example we have two multi-enum fields continents and countries. We will make the logic that depending on selected continents only countries of those continents will be available for selection.

1. Create (or open if exists) a file custom/Espo/Custom/Resources/metadata/clientDefs/YourEntityType.json (YourEntityType is the name of your entity type):

{
    "dynamicHandler": "custom:my-dynamic-handler"
}

2. Create a file client/custom/src/my-dynamic-handler.js:

define('custom:my-dynamic-handler', ['dynamic-handler'], (Dep) => {

    return class extends Dep {

        init() {
            this.controlFields();
            this.recordView.listenTo(this.model, 'change:continents', () => this.controlFields());
        }

        controlFields() {
            const selectedContinentList = this.recordView.model.get('continents') || [];

            const continentList = ['Africa', 'Asia', 'Europe', 'America'];

            const countryMap = {
                'Africa': ['Nigeria', 'Ethiopia'],
                'Asia': ['India', 'Pakistan'],
                'Europe': ['United Kingdom', 'France'],
                'America': ['United States', 'Canada', 'Brazil'],
            };

            const countryList = [];

            for (const continent of selectedContinentList) {
                countryList = countryList.concat(
                    countryMap[continent] || []
                );
            }

            this.recordView.setFieldOptionList('countries', countryList);
        }
    }
});

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