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tsa - Typescript source code analysis and documentation tool

This library extracts information from typescript source code that can be used for documentation generation. It produces result compatible with x/deno_doc@0.62.0, but uses Typescript Compiler to detect variable types.

Itā€™s similar to npm:typedoc, but works with Deno standards:

  • uses .ts filename extension in module specifiers
  • allows to import remote modules
  • allows to use lib.deno.ns.d.ts library to support Deno built-in objects

Example:

// To download and run this example:
// curl 'https://raw.githubusercontent.com/jeremiah-shaulov/tsa/v0.0.8/README.md' | perl -ne '$y=$1 if /^```(ts\\b)?/;  print $_ if $y&&$m;  $m=$y&&($m||m~^// deno .*?/example1.ts~)' > /tmp/example1.ts
// deno run --allow-env --allow-net --allow-read --allow-write /tmp/example1.ts

import {tsa, printDiagnostics, LoadOptions, EmitDocOptions} from 'https://deno.land/x/tsa@v0.0.8/mod.ts';

/**	Options for typescript compiler.
 **/
export const compilerOptions: tsa.CompilerOptions =
{	declaration: true,
    emitDeclarationOnly: true,
    allowSyntheticDefaultImports: true,
    lib: ['lib.esnext.d.ts', 'lib.deno.ns.d.ts'],
};

/**	Configures how to resolve module specifiers, and how to load module contents.
 **/
export const loadOptions: LoadOptions =
{
};

/**	Configures what symbols to include in the result.
    By default it works like `doc` from `x/deno_doc`.
 **/
export const emitDocOptions: EmitDocOptions =
{
};

/**	Generate doc for the current module, and write it to the provided filename.
    @param filename Where to save the doc in JSON format.
 **/
export async function writeSelfDocToFile(filename: string)
{	const program = await tsa.createDenoProgram([import.meta.url], compilerOptions, loadOptions);
    printDiagnostics(tsa.getPreEmitDiagnostics(program));
    const docNodes = program.emitDoc(emitDocOptions);
    await Deno.writeTextFile(filename, JSON.stringify(docNodes, undefined, '\t'));
    console.log('%c%d doc-nodes %cwritten to %s', 'color:green', docNodes.length, '', filename);
}

// Save to `/tmp/doc.json`
await writeSelfDocToFile('/tmp/doc.json');

Whatā€™s not supported

Currently npm: schema in module specifiers is not supported. To avoid reinventing the wheel, iā€™ll wait for x/deno_graph to start supporting this.

How to use from command line

First install the tool:

deno install --allow-env --allow-net --allow-read --allow-write https://deno.land/x/tsa@v0.0.8/tsa.ts

You can use tsa as you use tsc for generating JavaScript or DTS (other usage patterns are not supported). And it will do the same operations as tsc would, but on project that follows Deno standards.

Plus tsa can generate source code AST. To do this specify --outFile to a file with .json extension.

tsa --declaration --emitDeclarationOnly --outFile /tmp/ast.json 'https://deno.land/x/mysql@v2.11.0/mod.ts'

How to use from Deno projects

This library exports the following symbols:

  • tsa - Namespace that contains everything from the underlying Typescript Compiler. Itā€™s the same namespace that npm:typescript exports, with 2 extensions:
    1. type DenoProgram, that is extension of Program, that adds emitDoc() method
    2. function createDenoProgram(), that is similar to createProgram(), but returns DenoProgram instead of Program
  • LoadOptions - Configures how to resolve module specifiers, and how to load module contents
  • defaultResolve() - Function that is used by default if LoadOptions.resolve() is not set
  • defaultLoad() - Function that is used by default if LoadOptions.load() is not set. It loads from files or external URLs, and caches external resources.
  • EmitDocOptions - Options for DenoProgram.emitDoc()
  • formatDiagnostics() - Calls one of tsa.formatDiagnostics() or tsa.formatDiagnosticsWithColorAndContext() depending on the value of Deno.noColor
  • printDiagnostics() - Prints the result of formatDiagnostics() to stderr
  • Type DocNode, array of which DenoProgram.emitDoc() returns. Itā€™s assignable to the DocNode from x/deno_doc@0.62.0, but contains more information
  • Types for DocNode fields: DocNodeKind, DocNodeFunction, DocNodeVariable, DocNodeClass, and many more They are assignable to the same types from x/deno_doc@0.62.0.
function DenoProgram.createDenoProgram(entryPoints: readonly string[], compilerOptions?: tsa.CompilerOptions, loadOptions?: LoadOptions): Promise<tsa.DenoProgram>;

type DenoProgram = tsa.Program & {emitDoc(options?: EmitDocOptions): DocNode[]};

How the result is different from deno_doc?

DenoProgram.emitDoc() returns array of DocNode objects, like doc() from x/deno_doc does. To understand the information each DocNode contains, you need to start from learning x/deno_doc.

This library adds additional information to DocNode:

  • Location has additional entryPointNumber field. You can pass relative paths to createDenoProgram() as entry points, but Location.filename always contains corresponding absolute URL. If this filename is one of the entry points, the entryPointNumber field will contain the index in entryPoints array.
  • DocNode has additional exports field. If a symbol is reexported from several places, those places will be recorded here (including current location). Also if this node is returned as DeclarationKind != 'export', but the symbol is exported from some other entry point or traversed file, exports will contain 1 record for the export.
  • ClassPropertyDef has additional init field that contains property initializer (if any).
  • EnumDef has additional isConst field for const enums.
  • Doc-comments are returned not only as doc string, but also docTokens, that have separate parts for comment text and @link tags.
  • JsDocTagTyped (for @enum, @extends, @this and @type tags) and JsDocTagParam (for @param) have additional tsType field for the object type.
  • JsDocTagNamed (for @callback and @template tags) has additional tsType and typeParams fields.
  • DecoratorDef has additional nodeIndex field that contains node index in the results where this decorator function is returned, if itā€™s returned. To include referenced symbols in the result, use EmitDocOptions.includeReferenced option.
  • References to another named types are returned as TsTypeRefDef objects that contain not only typeName, but also additional nodeIndex field, that contains index in the results for this type. If the type is an enum member, also nodeSubIndex will be set to member number. See EmitDocOptions.includeReferenced.
  • ClassDef has additional superNodeIndex field, that contains node index in the results for the super class. See EmitDocOptions.includeReferenced.

Configuration options for the Typescript Compiler (tsa.CompilerOptions)

You can pass tsa.CompilerOptions to tsa.createDenoProgram(). It works in the same fashion as typescript.CompilerOptions for typescript.createProgram(), with the following differences:

  • lib has 2 additional options that you can provide: lib.deno.ns.d.ts and lib.deno.unstable.d.ts. If you donā€™t specify lib explicitly, the default is lib.deno.ns.d.ts.
  • default value for allowJs is true.
  • default value for target is tsa.ScriptTarget.ESNext.
  • default value for module is tsa.ModuleKind.ESNext.
  • regardless of allowImportingTsExtensions value, module specifiers must include .ts (or different) extension.

Module resolution and loading options (LoadOptions)

You can pass LoadOptions to tsa.createDenoProgram() that allow to configure the way modules are resolved and loaded.

type LoadOptions =
{	importMap?: string|URL;
    resolve?(specifier: string, referrer: string): string;
    load?(specifier: string, isDynamic: boolean): Promise<LoadResponse|undefined>;
};
  • importMap - An optional URL or path to an import map to be loaded and used to resolve module specifiers. If both importMap and resolve() are specified, the importMap will be preferred.
  • resolve() - An optional callback that allows the default resolution logic of the module graph to be ā€œoverriddenā€. This is intended to allow items like an import map to be used with the module graph. The callback takes the string of the module specifier, as it appears in import from or export from, and the string URL of the module where this import is found. The callback then returns a resolved URL to the module file.
  • load() - An optional callback that is called with the URL string of the resource to be loaded. The callback should return a LoadResponse or undefined if the module is not found. If there are other errors encountered, a rejected promise should be returned.

For example LoadOptions allow to substitute source code of a module during loading.

// To download and run this example:
// curl 'https://raw.githubusercontent.com/jeremiah-shaulov/tsa/v0.0.8/README.md' | perl -ne '$y=$1 if /^```(ts\\b)?/;  print $_ if $y&&$m;  $m=$y&&($m||m~^// deno .*?/example2.ts~)' > /tmp/example2.ts
// deno run --allow-env --allow-net --allow-read --allow-write /tmp/example2.ts

import {tsa, defaultLoad, printDiagnostics} from 'https://deno.land/x/tsa@v0.0.8/mod.ts';

/**	Generate doc for the current module, and write it to the provided filename.
    @param filename Where to save the doc in JSON format.
 **/
export async function writeSelfDocToFile(filename: string)
{	const program = await tsa.createDenoProgram
    (	[import.meta.url],
        {	declaration: true,
            emitDeclarationOnly: true,
            allowSyntheticDefaultImports: true,
        },
        {	async load(specifier, isDynamic)
            {	const result = await defaultLoad(specifier, isDynamic);
                if (result?.kind == 'module')
                {	result.content =
                    `	/**	Example module.
                            @module
                         **/
                        ${result.content}
                    `;
                }
                return result;
            }
        }
    );
    printDiagnostics(tsa.getPreEmitDiagnostics(program));
    const docNodes = program.emitDoc();
    await Deno.writeTextFile(filename, JSON.stringify(docNodes, undefined, '\t'));
    console.log('%c%d doc-nodes %cwritten to %s', 'color:green', docNodes.length, '', filename);
}

// Save to `/tmp/doc.json`
await writeSelfDocToFile('/tmp/doc.json');

EmitDocOptions

You can pass options to DenoProgram.emitDoc() that affect what files to traverse, and what symbols to include in the result.

type EmitDocOptions =
{	followModuleImports?: boolean;
    includeReferenced?: boolean;
    includeBuiltIn?: boolean;
    ignoreIgnoreTag?: boolean;
    noImportNodes?: boolean;
    includeSymbol?(symbol: tsa.Symbol, isExported: boolean, checker: tsa.TypeChecker): boolean;
};
  • followModuleImports - Work not only on entry points, but on every module that appears in import from or export from statements.
  • includeReferenced - DocNodes in the result can reference another symbols. Symbol names can appear in type aliases, type parameters, etc. Also decorators refer to functions defined somewhere, not necessarily in entry point modules. If this flag is set to true, referenced symbols will be included in the result, and their indices in the resulting array will be recorded in the nodes that refer to them. The referrers include: DecoratorDef.nodeIndex, TsTypeRefDef.nodeIndex and TsTypeRefDef.nodeSubIndex (for enum members), and ClassDef.superNodeIndex.
  • includeBuiltIn - Also generate docs for referenced built-in objects, like Map, HTMLElement, etc.
  • ignoreIgnoreTag - By default symbols marked with @ignore tag in their doc-comments, will not be included in the result. Set this to true to ignore the ignore.
  • noImportNodes - By default, for every symbol that appears in import from statement there will be corresponding DocNode with kind == 'import'. Set this to true to exclude such nodes from the result.
  • includeSymbol() - Callback function that will be called to ask you whether you want to include every occured symbol in the source files to the result. By default only exported symbols are processed, and if you set EmitDocOptions.includeReferenced, also not exported but referenced ones. Specify this callback to potentially include other symbols.

I want to use different tsc version

This library contains typescript compiler inside, and itā€™s version is predefined when the library is packaged.

// To download and run this example:
// curl 'https://raw.githubusercontent.com/jeremiah-shaulov/tsa/v0.0.8/README.md' | perl -ne '$y=$1 if /^```(ts\\b)?/;  print $_ if $y&&$m;  $m=$y&&($m||m~^// deno .*?/example3.ts~)' > /tmp/example3.ts
// deno run --allow-env --allow-net --allow-read --allow-write /tmp/example3.ts

import {tsa} from 'https://deno.land/x/tsa@v0.0.8/mod.ts';
console.log(tsa.version);

Thereā€™s no guarantee that it can work with different tsc version, but iā€™ll show you one hack that allows to substitute the tsc:

// To download and run this example:
// curl 'https://raw.githubusercontent.com/jeremiah-shaulov/tsa/v0.0.8/README.md' | perl -ne '$y=$1 if /^```(ts\\b)?/;  print $_ if $y&&$m;  $m=$y&&($m||m~^// deno .*?/example4.ts~)' > /tmp/example4.ts
// deno run --allow-env --allow-net --allow-read --allow-write /tmp/example4.ts

import {tsa} from 'https://deno.land/x/tsa@v0.0.8/mod.ts';

// Different version of typescript
import tsaSubstitute from 'npm:typescript@3.9.3';

const entryPoint = 'https://deno.land/x/case@2.1.1/mod.ts';

// Use `call()` to substitute the typescript namespace
const program = await tsa.createDenoProgram.call(tsaSubstitute, [entryPoint]);

const docNodes = program.emitDoc();
await Deno.writeTextFile('/tmp/doc.json', JSON.stringify(docNodes, undefined, '\t'));