swc_ecma_transforms_typescript 48.0.0

Transforms TypeScript syntax into standard JavaScript.

Use [strip] when the input was parsed as TypeScript. If the input was parsed with swc_ecma_parser::Syntax::Flow, call [typescript] with [Config] and set [Config::flow_syntax] to true so Flow-specific cleanup runs after stripping type-only syntax.

use swc_common::{sync::Lrc, FileName, Globals, Mark, SourceMap, GLOBALS};
use swc_ecma_ast::EsVersion;
use swc_ecma_codegen::to_code_default;
use swc_ecma_parser::{parse_file_as_program, FlowSyntax, Syntax};
use swc_ecma_transforms_base::{fixer::fixer, resolver};
use swc_ecma_transforms_typescript::typescript;

let cm: Lrc<SourceMap> = Default::default();
let fm = cm.new_source_file(
    FileName::Custom("input.js".into()).into(),
    "const value: number = 1;",
);
let mut recovered_errors = Vec::new();

let program = parse_file_as_program(
    &fm,
    Syntax::Flow(FlowSyntax::default()),
    EsVersion::latest(),
    None,
    &mut recovered_errors,
)
.expect("flow should parse");
assert!(recovered_errors.is_empty());

GLOBALS.set(&Globals::default(), || {
    let unresolved_mark = Mark::new();
    let top_level_mark = Mark::new();

    let program = program
        .apply(resolver(unresolved_mark, top_level_mark, false))
        .apply(typescript(
            typescript::Config {
                flow_syntax: true,
                ..Default::default()
            },
            unresolved_mark,
            top_level_mark,
        ))
        .apply(fixer(None));

    let output = to_code_default(cm, None, &program);
    assert_eq!(output, "const value = 1;\n");
});