init commit

Author: mstn

.gitignore

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+# Deploy dirs
+lib
+npm
+
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# Typescript v1 declaration files
+typings/
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env
+
+# next.js build output
+.next

LICENSE

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+MIT License
+
+Copyright (c) 2018 mstn
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# Typescript type for fixed size arrays
+
+This package contains type definitions for arrays of fixed length in Typescript.
+The size of the arrays is checked **at compile time**.
+
+It could be useful in a variety of cases. For example, checking if the correct number of
+configuration options are passed to a function.
+
+At the moment, we can use only immutable arrays since arithmetic operations over numeric literals have not been implemented in Typescript, yet.
+Workarounds without using numeric literals (e.g. define numbers by recursion) look too hacky and impractical, but any suggestion is welcome!
+
+## Bugs and issues
+
+Apparently, the package works as expected for many practical cases.
+Howerver, I do not know if its behavior is always correct.
+Feel free to open an issue on github if you meet something odd.
+
+## Example
+
+```javascript
+import { FixedSizeArray } from 'fixed-size-array';
+
+// define a string array of length 2
+let d: FixedSizeArray<2, string>;
+
+d = ['a', 'b']; // ok
+d[0] = 'a2'; // ok
+d[2] = 'c2'; // type error
+d = ['a']; // type error
+d = ['a', 'b', 'c']; // type error
+d = ['a', true]; // type error
+
+d.push('d'); // type error       
+
+// define an empty array of strings            
+let e: FixedSizeArray<0, string>;
+// we get an error, but it is not what we want
+// however, in this case void could be a better type
+// why do we want to define an immutable array of zero elements?                    
+e = []; // type error
+e = [] as string[]; // type error
+
+// with objects does not work, as wanted
+let o: FixedSizeArray<2, string>;
+o = {
+  length: 2,
+  0: 'a',
+  1: 'b'
+  // type error
+  // missing array methods
+}
+
+o = {
+  length: 2,
+  0: 'a',
+  1: 'b',
+  'l': 'c'
+  // type error
+  // spurious property name
+}
+
+```
+
+## Current problems and limitations
+
+```javascript
+interface Fun<N extends number, M extends number> {
+  (a: FixedSizeArray<N, number>): FixedSizeArray<M, number>;
+}
+let f: Fun<2,3>;
+
+// type error
+f = function(v: [number, number]) {
+  return [1,2,3]
+}
+
+// ok
+f = function(v: FixedSizeArray<2, number>) {
+  return [1,2,3]
+}
+
+//ok
+f([1,2]);
+```

package-lock.json

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+{
+  "name": "fixed-size-array",
+  "version": "0.0.0",
+  "description": "typescript types for fixed size arrays",
+  "types": "./src/index.d.ts",
+  "scripts": {
+    "deploy": "./scripts/deploy.sh"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/mstn/fixed-size-array.git"
+  },
+  "keywords": [
+    "typescript",
+    "array"
+  ],
+  "author": "[email protected]",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/mstn/fixed-size-array/issues"
+  },
+  "homepage": "https://github.com/mstn/fixed-size-array#readme",
+  "devDependencies": {
+    "typescript": "^2.7.2"
+  }
+}

package.json

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+#!/bin/bash
+
+# cleanup lib directory
+rm -rf lib || exit 0;
+mkdir lib;
+
+# cp *.d.ts files
+# avoid inclusion of test files
+cp ./src/*.d.ts  ./lib
+
+# build vanilla package.json
+node -e "var package = require('./package.json'); \
+  delete package.scripts; \
+  delete package.options; \
+  delete package.devDependencies; \
+  package.types = 'index.d.ts'; \
+  var fs = require('fs'); \
+  fs.writeFileSync('./lib/package.json', JSON.stringify(package, null, 2)); \
+  "
+
+# Copy to ./npm
+cp README.md lib/
+cp LICENSE lib/
+
+# publish to npm
+cd lib && npm publish --access public

scripts/deploy.sh

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+// we use numeric literal types for length as TS 2.7 does for fixed size tuples
+// N is the length of the array
+// T is the type of array elements
+// M is a dummy type inizialized to '0', we need it to trick the compiler
+export type FixedSizeArray<N extends number, T, M extends string = '0'> = {
+    [k in M]: any;
+} & { length: N } & ReadonlyArray<T>;

src/index.d.ts

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+import { FixedSizeArray } from './';
+
+let d: FixedSizeArray<2, string>;
+
+d = ['a', 'b']; // ok
+d[0] = 'a2'; // ok
+d[2] = 'c2'; // type error
+d = ['a']; // type error
+d = ['a', 'b', 'c']; // type error
+d = ['a', true]; // type error
+
+d.push('d'); // type error
+
+let o: FixedSizeArray<2, string>;
+o = {
+  length: 2,
+  0: 'a',
+  1: 'b'
+  // type error
+  // missing array methods
+}
+
+o = {
+  length: 2,
+  0: 'a',
+  1: 'b',
+  'l': 'c'
+  // type error
+  // spurious property name
+}
+
+interface Fun<N extends number, M extends number> {
+  (a: FixedSizeArray<N, number>): FixedSizeArray<M, number>;
+}
+let f: Fun<2,3>;
+
+// type error
+f = function(v: [number, number]) {
+  return [1,2,3]
+}
+
+f = function(v: FixedSizeArray<2, number>) {
+  return [1,2,3]
+}
+f([1,2]);
+
+let g: [number, number];
+let h: FixedSizeArray<2, number>;
+
+h = [1, 2];
+g = [1, 2];
+
+h = g;
+// type error
+g = h;

src/test.ts

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+{
+  "compilerOptions": {
+    /* Basic Options */
+    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
+    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    // "lib": [],                             /* Specify library files to be included in the compilation. */
+    // "allowJs": true,                       /* Allow javascript files to be compiled. */
+    // "checkJs": true,                       /* Report errors in .js files. */
+    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
+    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
+    // "sourceMap": true,                     /* Generates corresponding '.map' file. */
+    // "outFile": "./",                       /* Concatenate and emit output to single file. */
+    // "outDir": "./",                        /* Redirect output structure to the directory. */
+    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
+    // "removeComments": true,                /* Do not emit comments to output. */
+    // "noEmit": true,                        /* Do not emit outputs. */
+    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
+    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
+    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
+
+    /* Strict Type-Checking Options */
+    "strict": true,                           /* Enable all strict type-checking options. */
+    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
+    // "strictNullChecks": true,              /* Enable strict null checks. */
+    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
+    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
+    // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
+    // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */
+
+    /* Additional Checks */
+    // "noUnusedLocals": true,                /* Report errors on unused locals. */
+    // "noUnusedParameters": true,            /* Report errors on unused parameters. */
+    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
+    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */
+
+    /* Module Resolution Options */
+    // "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
+    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
+    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
+    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
+    // "typeRoots": [],                       /* List of folders to include type definitions from. */
+    // "types": [],                           /* Type declaration files to be included in compilation. */
+    // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
+    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
+
+    /* Source Map Options */
+    // "sourceRoot": "./",                    /* Specify the location where debugger should locate TypeScript files instead of source locations. */
+    // "mapRoot": "./",                       /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
+    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
+
+    /* Experimental Options */
+    // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
+    // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
+  }
+}