{"id":31621035,"url":"https://github.com/premshree/monads-typescript","last_synced_at":"2025-10-06T15:49:06.982Z","repository":{"id":40762928,"uuid":"275840930","full_name":"premshree/monads-typescript","owner":"premshree","description":"Monadic Types and implementation for TypeScript 🚀","archived":false,"fork":false,"pushed_at":"2023-01-06T10:16:44.000Z","size":933,"stargazers_count":4,"open_issues_count":9,"forks_count":0,"subscribers_count":0,"default_branch":"master","last_synced_at":"2025-08-22T18:58:35.068Z","etag":null,"topics":["category-theory","functional-programming","javascript","math","monad","monads","typescript"],"latest_commit_sha":null,"homepage":"","language":"TypeScript","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/premshree.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null}},"created_at":"2020-06-29T14:35:13.000Z","updated_at":"2024-11-08T23:14:38.000Z","dependencies_parsed_at":"2023-02-05T20:46:58.776Z","dependency_job_id":null,"html_url":"https://github.com/premshree/monads-typescript","commit_stats":null,"previous_names":["premshree/monad.ts"],"tags_count":2,"template":false,"template_full_name":null,"purl":"pkg:github/premshree/monads-typescript","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/premshree%2Fmonads-typescript","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/premshree%2Fmonads-typescript/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/premshree%2Fmonads-typescript/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/premshree%2Fmonads-typescript/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/premshree","download_url":"https://codeload.github.com/premshree/monads-typescript/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/premshree%2Fmonads-typescript/sbom","scorecard":{"id":744522,"data":{"date":"2025-08-11","repo":{"name":"github.com/premshree/monads-typescript","commit":"f29157ea59780c9192d8c61b57ff7a7f0d77b0ed"},"scorecard":{"version":"v5.2.1-40-gf6ed084d","commit":"f6ed084d17c9236477efd66e5b258b9d4cc7b389"},"score":1.3,"checks":[{"name":"Dangerous-Workflow","score":-1,"reason":"no workflows found","details":null,"documentation":{"short":"Determines if the project's GitHub Action workflows avoid dangerous patterns.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#dangerous-workflow"}},{"name":"Packaging","score":-1,"reason":"packaging workflow not detected","details":["Warn: no GitHub/GitLab publishing workflow detected."],"documentation":{"short":"Determines if the project is published as a package that others can easily download, install, easily update, and uninstall.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#packaging"}},{"name":"Binary-Artifacts","score":10,"reason":"no binaries found in the repo","details":null,"documentation":{"short":"Determines if the project has generated executable (binary) artifacts in the source repository.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#binary-artifacts"}},{"name":"Token-Permissions","score":-1,"reason":"No tokens found","details":null,"documentation":{"short":"Determines if the project's workflows follow the principle of least privilege.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#token-permissions"}},{"name":"Code-Review","score":0,"reason":"Found 0/7 approved changesets -- score normalized to 0","details":null,"documentation":{"short":"Determines if the project requires human code review before pull requests (aka merge requests) are merged.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#code-review"}},{"name":"Maintained","score":0,"reason":"0 commit(s) and 0 issue activity found in the last 90 days -- score normalized to 0","details":null,"documentation":{"short":"Determines if the project is \"actively maintained\".","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#maintained"}},{"name":"Pinned-Dependencies","score":-1,"reason":"no dependencies found","details":null,"documentation":{"short":"Determines if the project has declared and pinned the dependencies of its build process.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#pinned-dependencies"}},{"name":"CII-Best-Practices","score":0,"reason":"no effort to earn an OpenSSF best practices badge detected","details":null,"documentation":{"short":"Determines if the project has an OpenSSF (formerly CII) Best Practices Badge.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#cii-best-practices"}},{"name":"Security-Policy","score":0,"reason":"security policy file not detected","details":["Warn: no security policy file detected","Warn: no security file to analyze","Warn: no security file to analyze","Warn: no security file to analyze"],"documentation":{"short":"Determines if the project has published a security policy.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#security-policy"}},{"name":"License","score":0,"reason":"license file not detected","details":["Warn: project does not have a license file"],"documentation":{"short":"Determines if the project has defined a license.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#license"}},{"name":"Fuzzing","score":0,"reason":"project is not fuzzed","details":["Warn: no fuzzer integrations found"],"documentation":{"short":"Determines if the project uses fuzzing.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#fuzzing"}},{"name":"Signed-Releases","score":-1,"reason":"no releases found","details":null,"documentation":{"short":"Determines if the project cryptographically signs release artifacts.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#signed-releases"}},{"name":"Branch-Protection","score":0,"reason":"branch protection not enabled on development/release branches","details":["Warn: branch protection not enabled for branch 'master'"],"documentation":{"short":"Determines if the default and release branches are protected with GitHub's branch protection settings.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#branch-protection"}},{"name":"SAST","score":0,"reason":"SAST tool is not run on all commits -- score normalized to 0","details":["Warn: 0 commits out of 8 are checked with a SAST tool"],"documentation":{"short":"Determines if the project uses static code analysis.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#sast"}},{"name":"Vulnerabilities","score":0,"reason":"26 existing vulnerabilities detected","details":["Warn: Project is vulnerable to: GHSA-968p-4wvh-cqc8","Warn: Project is vulnerable to: GHSA-67hx-6x53-jw92","Warn: Project is vulnerable to: GHSA-v88g-cgmw-v5xw","Warn: Project is vulnerable to: GHSA-93q8-gq69-wqmw","Warn: Project is vulnerable to: GHSA-v6h2-p8h4-qcjw","Warn: Project is vulnerable to: GHSA-grv7-fg5c-xmjg","Warn: Project is vulnerable to: GHSA-3xgq-45jj-v275","Warn: Project is vulnerable to: GHSA-gxpj-cx7g-858c","Warn: Project is vulnerable to: GHSA-w573-4hg7-7wgq","Warn: Project is vulnerable to: GHSA-fjxv-7rqg-78g4","Warn: Project is vulnerable to: GHSA-43f8-2h32-f4cj","Warn: Project is vulnerable to: GHSA-896r-f27r-55mw","Warn: Project is vulnerable to: GHSA-9c47-m6qq-7p4h","Warn: Project is vulnerable to: GHSA-29mw-wpgm-hmr9","Warn: Project is vulnerable to: GHSA-35jh-r3h4-6jhm","Warn: Project is vulnerable to: GHSA-952p-6rrq-rcjv","Warn: Project is vulnerable to: GHSA-f8q6-p94x-37v3","Warn: Project is vulnerable to: GHSA-xvch-5gv4-984h","Warn: Project is vulnerable to: GHSA-5fw9-fq32-wv5p","Warn: Project is vulnerable to: GHSA-hrpp-h998-j3pp","Warn: Project is vulnerable to: GHSA-p8p7-x288-28g6","Warn: Project is vulnerable to: GHSA-c2qf-rxjj-qqgw","Warn: Project is vulnerable to: GHSA-jgrx-mgxx-jf9v","Warn: Project is vulnerable to: GHSA-72xf-g2v4-qvf3","Warn: Project is vulnerable to: GHSA-j8xg-fqg3-53r7","Warn: Project is vulnerable to: GHSA-3h5v-q93c-6h6q"],"documentation":{"short":"Determines if the project has open, known unfixed vulnerabilities.","url":"https://github.com/ossf/scorecard/blob/f6ed084d17c9236477efd66e5b258b9d4cc7b389/docs/checks.md#vulnerabilities"}}]},"last_synced_at":"2025-08-22T18:21:23.400Z","repository_id":40762928,"created_at":"2025-08-22T18:21:23.400Z","updated_at":"2025-08-22T18:21:23.400Z"},"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":278638124,"owners_count":26019941,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","status":"online","status_checked_at":"2025-10-06T02:00:05.630Z","response_time":65,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["category-theory","functional-programming","javascript","math","monad","monads","typescript"],"created_at":"2025-10-06T15:49:03.291Z","updated_at":"2025-10-06T15:49:06.976Z","avatar_url":"https://github.com/premshree.png","language":"TypeScript","readme":"# monads-typescript\n\nIn functional programming, a [monad](https://en.wikipedia.org/wiki/Monad_(functional_programming)) is a design pattern that allows structuring programs generically while automating away boilerplate code needed by the program logic.\n\nIn a strongly typed liked language like Scala, with built-in types like the `Option` type, you are very likely\nto have already used or will eventually end up using monads without even knowing you are using them. This project\nis my attempt at understanding monads by writing them, and I decided to use TypeScript because it forces me to\nbuild monads from \"scratch\", but with support for strong typing.\n\n### Installation\n\n```\nnpm i monads-typescript\n```\n\n### Usage\n\nImport the appropriate static methods from the library like so:\n\n```ts\nimport { left, right } from 'monads-typescript';\nimport { maybe } from 'monads-typescript';\n...\n```\n\n### `Maybe` Monad\nThe first monad, the `Maybe` monad, is based on Scala's\n[`Option`](https://www.scala-lang.org/api/current/scala/Option.html) type. It's very useful when you want\nto encapsulate computation on values that might be `null` or `undefined`.\n\nHere's an example of some code you might find yourself writing in JavaScript/TypeScript:\n\n```ts\nconst greetUser = (userId) =\u003e {\n  const user = getUser(userId);\n  let name;\n  if (user) {\n    name = user.getName();\n  }\n  if (name) {\n    return `Hello ${name}`;\n  } else {\n    return 'Hello, guest';\n  }   \n}\n``` \n\nUsing the `Maybe` monad:\n\n```ts\nconst greetUser = (userId: number) =\u003e {\n  return maybe(getUser(userId))\n    .map((user) =\u003e user.getName())\n    .map((name) =\u003e `Hello, ${name}`)\n    .getOrElse('Hello, guest');\n};\n```\n\nDepending on your application, you could simplify this even further, like so:\n\n```ts\nconst getName = (user: User) =\u003e user.getName();\nconst greetName = (name: string) =\u003e `Hello, ${name}`;\n\nconst greetUser = (userId: number) =\u003e {\n  return maybe(getUser(userId))\n    .map(getName)\n    .map(greetName)\n    .getOrElse(greetName('guest'));\n};\n``` \n\nAs you can see, using the `Maybe` monad abstracts away a lot of boilerplate, giving you a flat, composable\ninterface to work with that's much more readable.\n\n### `Either` Monad\nSimilarly, the `Either` monad is based on Scala's\n[`Either`](https://www.scala-lang.org/api/current/scala/util/Either.html) type.\n\nThe `Either` monad is useful when you want to represent one of two possible types. An instance of\n`Either` is either a `Left` or `Right`. By convention, `Right` is used to represent a success type, while\n`Left` is used to hold a failure type.\n\nHere's another example of some code you might write in imperative TypeScript:\n\n```ts\nconst getAge = (uid: number): number | never =\u003e ...;\nconst canDrink = (age: number): boolean =\u003e age \u003e= 18;\n\nconst okToDrink = (uid: number) =\u003e {\n  try {\n    const age = getAge(uid);\n    if (age) {\n      return canDrink(age);\n    } \n  } catch {\n    return false;\n  }\n} \n```\n\nRewriting this using the `Either` monad:\n\n```ts\nconst getAge = (uid: number): Either\u003cstring, number\u003e =\u003e ...; // the left represents an error string\nconst canDrink = (age: number): boolean =\u003e age \u003e= 18;\n\nconst okToDrink = (uid: number) =\u003e {\n  getAge(uid).fold(\n    (error) =\u003e {\n      console.log(`Error getting age: ${error}`);\n      return false;\n    },\n    (age) =\u003e canDrink(age)\n  )\n}\n```\n\n### Resources\n- [Demystifying the Monad in Scala, Sinisa Louc](https://medium.com/free-code-camp/demystifying-the-monad-in-scala-cc716bb6f534), a well-written, technical, yet approachable explanation of monads in Scala.\n- [Douglas Crockford, Monads and Gonads, Google Tech Talks](https://www.youtube.com/watch?v=b0EF0VTs9Dc) Most talks about Monads involve some assumption that types are essential in creating\nmonadic abstractions. This talk is a refreshing non-academic take on _why_ we need monads (in programming) to begin with, and how you could build one in vanilla (untyped) JavaScript.\n\n### Other JavaScript/TypeScript implementations \n- [monad.js](https://github.com/chrislewis/monad.js), a vanilla JavaScipt implementation of Maybe and Either monads\n- [TsMonad](https://github.com/cbowdon/TsMonad), a TypeScript implementation of Maybe, Either and Writer monads","funding_links":[],"categories":[],"sub_categories":[],"project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fpremshree%2Fmonads-typescript","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fpremshree%2Fmonads-typescript","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fpremshree%2Fmonads-typescript/lists"}