stash/ui/v2.5/config/jest.preprocessor.js

const tsc       = require('typescript');
const tsConfig  = require('./../tsconfig.json');

module.exports = {
    process(src, path) {
        const isTs             = path.endsWith('.ts');
        const isTsx            = path.endsWith('.tsx');
        const isTypescriptFile = (isTs || isTsx);

        if ( isTypescriptFile ) {
            return tsc.transpileModule(
                src,
                {
                    compilerOptions: tsConfig.compilerOptions,
                    fileName:        path
                }
            ).outputText;
        }

        return src;
    },
};