Guide/Codegen

    Codegen

    Use printSync to turn a program AST back into source. Import it from @swc-next/core, the focused @swc-next/codegen package, or the initialized browser package.

    import { parseSync, printSync } from "@swc-next/core";

const { program } = parseSync("const answer = 1;");
program.body[0].declarations[0].init.value = 42;

console.log(printSync(program).code); // const answer = 42;

    Compact output

    import { parseSync, printSync } from "@swc-next/core";

const { program } = parseSync("const answer = 42;");
console.log(printSync(program, { minify: true }).code); // const answer=42;

    minify controls printing and whitespace. It does not perform the optimizations described under Minifier. Printing TypeScript also preserves types.

    Reference

    See the Codegen API for AST and metadata inputs, the output shape, and all formatting options. For a complete workflow, start with Parser and Walk.