Conditionalize Jest worker settings for CI to optimize performance.

Author: MartinBraquet

backend/api/jest.config.ts

@@ -27,7 +27,7 @@ module.exports = {
   collectCoverageFrom: ['src/**/*.{ts,tsx}', '!src/**/*.d.ts'],
   silent: true,
   // Each ts-jest worker is a full TS-compiling process; the default (cpus - 1) can spawn enough
-  // of them in parallel to exhaust memory on high-core-count machines.
-  maxWorkers: '50%',
-  workerIdleMemoryLimit: '512MB',
+  // of them in parallel to exhaust memory on high-core-count machines. CI runners only have a
+  // couple of cores, so throttling there just makes the suite slower without saving any memory.
+  ...(process.env.CI ? {} : {maxWorkers: '50%', workerIdleMemoryLimit: '512MB'}),
 }

backend/email/jest.config.ts

@@ -24,7 +24,7 @@ module.exports = {
   collectCoverageFrom: ['src/**/*.{ts,tsx}', '!src/**/*.d.ts'],
   silent: true,
   // Each ts-jest worker is a full TS-compiling process; the default (cpus - 1) can spawn enough
-  // of them in parallel to exhaust memory on high-core-count machines.
-  maxWorkers: '50%',
-  workerIdleMemoryLimit: '512MB',
+  // of them in parallel to exhaust memory on high-core-count machines. CI runners only have a
+  // couple of cores, so throttling there just makes the suite slower without saving any memory.
+  ...(process.env.CI ? {} : {maxWorkers: '50%', workerIdleMemoryLimit: '512MB'}),
 }

backend/shared/jest.config.ts

@@ -28,7 +28,7 @@ module.exports = {
   collectCoverageFrom: ['src/**/*.{ts,tsx}', '!src/**/*.d.ts'],
   silent: true,
   // Each ts-jest worker is a full TS-compiling process; the default (cpus - 1) can spawn enough
-  // of them in parallel to exhaust memory on high-core-count machines.
-  maxWorkers: '50%',
-  workerIdleMemoryLimit: '512MB',
+  // of them in parallel to exhaust memory on high-core-count machines. CI runners only have a
+  // couple of cores, so throttling there just makes the suite slower without saving any memory.
+  ...(process.env.CI ? {} : {maxWorkers: '50%', workerIdleMemoryLimit: '512MB'}),
 }

common/jest.config.ts

@@ -13,7 +13,7 @@ module.exports = {
   collectCoverageFrom: ['src/**/*.{ts,tsx}', '!src/**/*.d.ts'],
   silent: true,
   // Each ts-jest worker is a full TS-compiling process; the default (cpus - 1) can spawn enough
-  // of them in parallel to exhaust memory on high-core-count machines.
-  maxWorkers: '50%',
-  workerIdleMemoryLimit: '512MB',
+  // of them in parallel to exhaust memory on high-core-count machines. CI runners only have a
+  // couple of cores, so throttling there just makes the suite slower without saving any memory.
+  ...(process.env.CI ? {} : {maxWorkers: '50%', workerIdleMemoryLimit: '512MB'}),
 }

jest.config.ts

@@ -22,7 +22,7 @@ module.exports = {
   ],
   silent: true,
   // Each ts-jest worker is a full TS-compiling process; the default (cpus - 1) can spawn enough
-  // of them in parallel to exhaust memory on high-core-count machines.
-  maxWorkers: '50%',
-  workerIdleMemoryLimit: '512MB',
+  // of them in parallel to exhaust memory on high-core-count machines. CI runners only have a
+  // couple of cores, so throttling there just makes the suite slower without saving any memory.
+  ...(process.env.CI ? {} : {maxWorkers: '50%', workerIdleMemoryLimit: '512MB'}),
 }

web/jest.config.js

@@ -24,7 +24,7 @@ module.exports = {
   collectCoverageFrom: ['src/**/*.{ts,tsx}', '!src/**/*.d.ts'],
   silent: true,
   // Each ts-jest worker is a full TS-compiling process; the default (cpus - 1) can spawn enough
-  // of them in parallel to exhaust memory on high-core-count machines.
-  maxWorkers: '50%',
-  workerIdleMemoryLimit: '512MB',
+  // of them in parallel to exhaust memory on high-core-count machines. CI runners only have a
+  // couple of cores, so throttling there just makes the suite slower without saving any memory.
+  ...(process.env.CI ? {} : {maxWorkers: '50%', workerIdleMemoryLimit: '512MB'}),
 }