TypeScript/tests/cases/compiler/APISample_WatchWithDefaults.ts
2018-06-12 12:52:06 -07:00

60 lines
2.7 KiB
TypeScript

// @module: commonjs
// @skipLibCheck: true
// @includebuiltfile: typescriptServices.d.ts
// @noImplicitAny:true
// @strictNullChecks:true
// @filename: node_modules/typescript/index.d.ts
declare module "typescript" {
export = ts;
}
// @filename: APISample_WatchWithDefaults.ts
/*
* Note: This test is a public API sample. This uses default sys interface without having to pass anything
* Please log a "breaking change" issue for any API breaking change affecting this issue
*/
declare var console: any;
import ts = require("typescript");
function watchMain() {
const configPath = ts.findConfigFile(/*searchPath*/ "./", ts.sys.fileExists, "tsconfig.json");
if (!configPath) {
throw new Error("Could not find a valid 'tsconfig.json'.");
}
// TypeScript can use several different program creation "strategies":
// * ts.createEmitAndSemanticDiagnosticsBuilderProgram,
// * ts.createSemanticDiagnosticsBuilderProgram
// * ts.createAbstractBuilder
// The first two produce "builder programs". These use an incremental strategy to only re-check and emit files whose
// contents may have changed, or whose dependencies may have changes which may impact change the result of prior type-check and emit.
// The last uses an ordinary program which does a full type check after every change.
// Between `createEmitAndSemanticDiagnosticsBuilderProgram` and `createSemanticDiagnosticsBuilderProgram`, the only difference is emit.
// For pure type-checking scenarios, or when another tool/process handles emit, using `createSemanticDiagnosticsBuilderProgram` may be more desirable.
// Note that there is another overload for `createWatchCompilerHost` that takes a set of root files.
const host = ts.createWatchCompilerHost(configPath, {}, ts.sys);
// You can technically override any given hook on the host, though you probably don't need to.
// Note that we're assuming `origCreateProgram` and `origPostProgramCreate` doesn't use `this` at all.
const origCreateProgram = host.createProgram;
host.createProgram = (rootNames, options, host, oldProgram) => {
console.log("** We're about to create the program! **");
return origCreateProgram(rootNames, options, host, oldProgram);
}
const origPostProgramCreate = host.afterProgramCreate;
host.afterProgramCreate = program => {
console.log("** We finished making the program! **");
origPostProgramCreate!(program);
};
// `createWatchProgram` creates an initial program, watches files, and updates the program over time.
ts.createWatchProgram(host);
}
watchMain();