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Version: Next

ESM Support

To use ts-jest with ESM support:

ESM presets

There are also 3 presets to work with ESM.

Examples

Manual configuration

// jest.config.js
module.exports = {
// [...]
extensionsToTreatAsEsm: ['.ts'],
globals: {
'ts-jest': {
useESM: true,
},
},
moduleNameMapper: {
'^(\\.{1,2}/.*)\\.js$': '$1',
},
}
// OR package.json
{
// [...]
"jest": {
"extensionsToTreatAsEsm": [".ts"],
"globals": {
"ts-jest": {
"useESM": true
}
},
"moduleNameMapper": {
"^(\\.{1,2}/.*)\\.js$": "$1"
}
}
}

Use ESM presets

important

Starting from v28.0.0, ts-jest will gradually switch to esbuild/swc to transform ts to js. To make the transition smoothly, we introduce legacy presets as a fallback when the new codes don't work yet.

// jest.config.js
module.exports = {
// [...]
preset: 'ts-jest/presets/default-esm', // or other ESM presets
globals: {
'ts-jest': {
useESM: true,
},
},
moduleNameMapper: {
'^(\\.{1,2}/.*)\\.js$': '$1',
},
}
// OR package.json
{
// [...]
"jest": {
"preset": "ts-jest/presets/default-esm", // or other ESM presets,
"globals": {
"ts-jest": {
"useESM": true
}
},
"moduleNameMapper": {
"^(\\.{1,2}/.*)\\.js$": "$1"
}
}
}