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Last active January 11, 2023 16:38
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Simple Typescript package setup
Raw
README.md

Dead Simple package setup for Typescript

Steps

  1. Initial project folder setup:
mkdir mypackage                   # Create a new folder for your package
cd mypackage
pnpm init                         # Create a brand new package.json
pnpm add typescript vitest -D     # Add Typescript (bundler) and Vitest (testing)
  1. create this file structure: (You can choose whatever file structure you want, this aims to keep things simple and somewhat "organized"
mypackage
|- package.json
|- src/
| |- main.ts # Here you can name this file whatever you want and add as much entry points as you want. again, for simplicity, we just have _one_ entrypoint
|- dist/
  1. Update package.json (see the file below)
  2. Create a tsconfig.json file. I recomment you create the file with tsc --init because it will create it will all the commented options with a small explanation
  3. Update tsconfig.json (See the file below)
  4. now you can install and build by pnpm i and pnpm run build.
  5. The build step will generate the dist folder and all the exported files you defined in the tsconfig.json file.
  6. you can go to other project/package and
import {sum} from 'mypackage'

sum(4, 5) // 9!!!

Files Explanation

package.json

  • can asign any package name you want
  • can assign any version you want
  • "type": "module" is important for other projects to treat this one as a module. LOOKING FOR FEEDBACK HERE. It would be nice to understand better why we need this, I know is related to how the pacage will be treated (ESM or CJS) but I don't have a veru definitive answer to it.
  • the exports property is also important. This is the public access you are giving to other libraries/projects to use. it can be just "." as in here, or you can have separate entrypoints defined. You at least need to define where is the file located, and the types is a must for IDEs like VSCode to now where to look for the package types.
  • the attributes main, module and types for some reason are important for VSCode in order to match the module with teh types. Maybe this is a legacy issue? (the exports attributes is newer)

tsconfig.json

  • I want the library users to bundle properly the package, not deliver it bundled. that's why the target is ESNext. (If you have more information about this it would be fine to get feedback too!)
  • you can read all the options, I decided to choose the most common and simple ones.

Background and Context

At Mintter, we have a monorepo setup for all the code, not just the frontend. Up until now we were putting everything frontend-related inside the same project.

In December we released the Mintter gateway, which is a server that can render Publications on the web, not just inside the local application. This is forcing us to separate some pieces of the app in order to use it on the gateway code (right now is a separate NextJS app).

While I was researching about how to create a separate package for the shared code, I found that it was hard to find a place in which the Simplest solution using Typescript was explained.

This Gist aims to share the process I follow to create a separate Typescript library that can be consumed inside another app/package. Please follow the steps and let me know if you have any feedback!

Resources

Raw
main.ts
/**
Of course this is SUPER SIMPLE, but you can get the idea from this right? If not, please let me know!!
*/
export function sum(a: number, b: number): number {
return a + b
}
Raw
package.json
{
"name": "mypackage",
"version": "0.1.0",
"description": "",
"type": "module",
"exports": {
".": {
"types": "./dist/main.d.ts",
"import": "./dist/main.js"
}
},
"main": "./dist/main.js",
"module": "./dist/main.js",
"types": "./dist/main.d.ts",
"files": [
"dist"
],
"scripts": {
"dev": "tsc -w",
"build": "tsc ",
"test": "echo \"Error: no test specified\" && exit 1"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"typescript": "4.9.4",
"vitest": "0.25.5"
}
}
Raw
tsconfig.json
{
"compilerOptions": {
/* Visit https://aka.ms/tsconfig to read more about this file */
/* Projects */
// "incremental": true, /* Save .tsbuildinfo files to allow for incremental compilation of projects. */
// "composite": true, /* Enable constraints that allow a TypeScript project to be used with project references. */
// "tsBuildInfoFile": "./.tsbuildinfo", /* Specify the path to .tsbuildinfo incremental compilation file. */
// "disableSourceOfProjectReferenceRedirect": true, /* Disable preferring source files instead of declaration files when referencing composite projects. */
// "disableSolutionSearching": true, /* Opt a project out of multi-project reference checking when editing. */
// "disableReferencedProjectLoad": true, /* Reduce the number of projects loaded automatically by TypeScript. */
/* Language and Environment */
"target": "ESNext", /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
"lib": ["DOM", "DOM.Iterable", "ESNext"], /* Specify a set of bundled library declaration files that describe the target runtime environment. */
// "jsx": "preserve", /* Specify what JSX code is generated. */
// "experimentalDecorators": true, /* Enable experimental support for TC39 stage 2 draft decorators. */
// "emitDecoratorMetadata": true, /* Emit design-type metadata for decorated declarations in source files. */
// "jsxFactory": "", /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h'. */
// "jsxFragmentFactory": "", /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
// "jsxImportSource": "", /* Specify module specifier used to import the JSX factory functions when using 'jsx: react-jsx*'. */
// "reactNamespace": "", /* Specify the object invoked for 'createElement'. This only applies when targeting 'react' JSX emit. */
// "noLib": true, /* Disable including any library files, including the default lib.d.ts. */
// "useDefineForClassFields": true, /* Emit ECMAScript-standard-compliant class fields. */
// "moduleDetection": "auto", /* Control what method is used to detect module-format JS files. */
/* Modules */
"module": "ESNext", /* Specify what module code is generated. */
"rootDir": "./src", /* Specify the root folder within your source files. */
"moduleResolution": "node", /* Specify how TypeScript looks up a file from a given module specifier. */
// "baseUrl": "./", /* Specify the base directory to resolve non-relative module names. */
// "paths": {}, /* Specify a set of entries that re-map imports to additional lookup locations. */
// "rootDirs": [], /* Allow multiple folders to be treated as one when resolving modules. */
// "typeRoots": [], /* Specify multiple folders that act like './node_modules/@types'. */
"types": ["vitest/globals"], /* Specify type package names to be included without being referenced in a source file. */
// "allowUmdGlobalAccess": true, /* Allow accessing UMD globals from modules. */
// "moduleSuffixes": [], /* List of file name suffixes to search when resolving a module. */
"resolveJsonModule": true, /* Enable importing .json files. */
// "noResolve": true, /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */
/* JavaScript Support */
"allowJs": false, /* Allow JavaScript files to be a part of your program. Use the 'checkJS' option to get errors from these files. */
// "checkJs": true, /* Enable error reporting in type-checked JavaScript files. */
// "maxNodeModuleJsDepth": 1, /* Specify the maximum folder depth used for checking JavaScript files from 'node_modules'. Only applicable with 'allowJs'. */
/* Emit */
"declaration": true, /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
"declarationMap": true, /* Create sourcemaps for d.ts files. */
// "emitDeclarationOnly": true, /* Only output d.ts files and not JavaScript files. */
"sourceMap": true, /* Create source map files for emitted JavaScript files. */
// "outFile": "./", /* Specify a file that bundles all outputs into one JavaScript file. If 'declaration' is true, also designates a file that bundles all .d.ts output. */
"outDir": "./dist", /* Specify an output folder for all emitted files. */
"removeComments": true, /* Disable emitting comments. */
// "noEmit": true, /* Disable emitting files from a compilation. */
// "importHelpers": true, /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
// "importsNotUsedAsValues": "remove", /* Specify emit/checking behavior for imports that are only used for types. */
// "downlevelIteration": true, /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
// "sourceRoot": "", /* Specify the root path for debuggers to find the reference source code. */
// "mapRoot": "", /* Specify the location where debugger should locate map files instead of generated locations. */
// "inlineSourceMap": true, /* Include sourcemap files inside the emitted JavaScript. */
// "inlineSources": true, /* Include source code in the sourcemaps inside the emitted JavaScript. */
// "emitBOM": true, /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
// "newLine": "crlf", /* Set the newline character for emitting files. */
// "stripInternal": true, /* Disable emitting declarations that have '@internal' in their JSDoc comments. */
// "noEmitHelpers": true, /* Disable generating custom helper functions like '__extends' in compiled output. */
// "noEmitOnError": true, /* Disable emitting files if any type checking errors are reported. */
// "preserveConstEnums": true, /* Disable erasing 'const enum' declarations in generated code. */
"declarationDir": "./dist", /* Specify the output directory for generated declaration files. */
// "preserveValueImports": true, /* Preserve unused imported values in the JavaScript output that would otherwise be removed. */
/* Interop Constraints */
"isolatedModules": true, /* Ensure that each file can be safely transpiled without relying on other imports. */
// "allowSyntheticDefaultImports": true, /* Allow 'import x from y' when a module doesn't have a default export. */
"esModuleInterop": true, /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
// "preserveSymlinks": true, /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
"forceConsistentCasingInFileNames": true, /* Ensure that casing is correct in imports. */
/* Type Checking */
"strict": true, /* Enable all strict type-checking options. */
// "noImplicitAny": true, /* Enable error reporting for expressions and declarations with an implied 'any' type. */
// "strictNullChecks": true, /* When type checking, take into account 'null' and 'undefined'. */
// "strictFunctionTypes": true, /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
// "strictBindCallApply": true, /* Check that the arguments for 'bind', 'call', and 'apply' methods match the original function. */
// "strictPropertyInitialization": true, /* Check for class properties that are declared but not set in the constructor. */
// "noImplicitThis": true, /* Enable error reporting when 'this' is given the type 'any'. */
// "useUnknownInCatchVariables": true, /* Default catch clause variables as 'unknown' instead of 'any'. */
// "alwaysStrict": true, /* Ensure 'use strict' is always emitted. */
// "noUnusedLocals": true, /* Enable error reporting when local variables aren't read. */
// "noUnusedParameters": true, /* Raise an error when a function parameter isn't read. */
// "exactOptionalPropertyTypes": true, /* Interpret optional property types as written, rather than adding 'undefined'. */
// "noImplicitReturns": true, /* Enable error reporting for codepaths that do not explicitly return in a function. */
// "noFallthroughCasesInSwitch": true, /* Enable error reporting for fallthrough cases in switch statements. */
// "noUncheckedIndexedAccess": true, /* Add 'undefined' to a type when accessed using an index. */
// "noImplicitOverride": true, /* Ensure overriding members in derived classes are marked with an override modifier. */
// "noPropertyAccessFromIndexSignature": true, /* Enforces using indexed accessors for keys declared using an indexed type. */
// "allowUnusedLabels": true, /* Disable error reporting for unused labels. */
// "allowUnreachableCode": true, /* Disable error reporting for unreachable code. */
/* Completeness */
// "skipDefaultLibCheck": true, /* Skip type checking .d.ts files that are included with TypeScript. */
"skipLibCheck": true, /* Skip type checking all .d.ts files. */
},
"exclude": ["node_modules", "dist"]
}
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