outDir

outDir is a TypeScript compiler option that specifies the directory where emitted JavaScript files are written when TypeScript sources are compiled. It is configured in a tsconfig.json file under the compilerOptions section and directs the compiler to place all output files in a single, designated folder.

When outDir is used, the emitted JavaScript files preserve the folder structure of the input files relative to a root directory. The rootDir option can influence this mapping by identifying the root of the input file hierarchy; if rootDir is not set, the emitted structure mirrors the location of the input files. For example, with rootDir set to "./src" and outDir set to "./dist", a source file at src/app/main.ts will compile to dist/app/main.js.

outDir is commonly used to separate source code from build artifacts, enabling clean project organization and easier deployment. It also works in conjunction with other options such as sourceMap, which will typically emit source maps alongside the corresponding JavaScript files in the same output directory.

Note that if you use outFile to concatenate multiple inputs into a single file (for module targets that support concatenation), the outDir setting is not used for output. In that scenario, all output is written to the specified outFile path rather than into a directory.

See also: rootDir, outFile, tsconfig.json, compilerOptions.