initial commit

Author: lequanghuylc

.gitignore

@@ -0,0 +1 @@
+/node_modules

decorator.ts

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+import { isAsync } from './isAsync';
+
+export default function erria(
+  target: Object,
+  propertyName: string,
+  propertyDesciptor: PropertyDescriptor): any {
+
+  if (typeof target[propertyName] !== 'function') return;
+  const method = propertyDesciptor.value;
+
+  if (isAsync(method)) {
+    propertyDesciptor.value = async function (...args: any[]) {
+      try {
+        const result = await method.apply(this, args);
+        return [result, null];
+      } catch(err) {
+        return [null, err]
+      }
+    }
+  } else {
+    propertyDesciptor.value = function (...args: any[]) {
+      try {
+        const result = method.apply(this, args);
+        return [result, null];
+      } catch(err) {
+        return [null, err]
+      }
+    }
+  }
+
+  return propertyDesciptor;
+};

index.ts

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+import { isAsync, isPromise } from './isAsync';
+
+export default function erria(func : Function, ...args) : [any, Error] | Promise<[any, Error]> | any {
+  let useResolve = false;
+  try {
+    const exec = func(...args);
+    if (isPromise(exec)) {
+      useResolve = true;
+      return new Promise((resolve) => {
+        exec
+        .then(result => resolve([result, null]))
+        .catch(err => resolve([null, err]))
+      });
+    } else {
+      return [exec, null];
+    }
+  } catch(err) {
+    if (useResolve) {
+      return new Promise((resolve) => {
+        resolve([null, err])
+      });
+    } else {
+      return [null, err];
+    }
+  }
+};

isAsync.ts

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+// credit to stackoverflow
+
+export function isAsync (func) {
+  const string = func.toString().trim();
+
+  return !!(
+      // native
+      string.match(/^async /) ||
+      // babel (this may change, but hey...)
+      string.match(/return _ref[^\.]*\.apply/)
+      // insert your other dirty transpiler check
+
+      // there are other more complex situations that maybe require you to check the return line for a *promise*
+  );
+}
+
+export function isPromise (obj) {
+  return !!obj && (typeof obj === 'object' || typeof obj === 'function') && typeof obj.then === 'function';
+}

package.json

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+{
+  "name": "erria",
+  "version": "0.1.0",
+  "description": "return error in array, remove the need of using try catch",
+  "main": "index.ts",
+  "scripts": {
+    "test": "ts-node test.ts"
+  },
+  "keywords": [
+    "Error",
+    "Try",
+    "catch",
+    "typescript"
+  ],
+  "author": "Le Quang Huy <[email protected]>",
+  "license": "ISC",
+  "devDependencies": {
+    "ts-node": "^8.5.4",
+    "typescript": "^3.7.3"
+  }
+}

readme.md

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+## Erria
+
+**Erria** (Error in array) is inspired by the way Golang function can return mutiple value. Reduce the need of try catch code blocks.
+
+## Install
+
+```
+yarn add erria
+```
+or
+```
+npm i --save erria
+```
+
+## Usage
+
+This module is written in Typescript, pull requesta for regular js project are welcomed
+
+### Regular synchronous and asynchronous function
+
+```
+  import erria from 'erria';
+
+  const start = async () => {
+    const [res, err] = await erria(simpleAsync, someParameter, someMoreParameter);
+    console.log([res, err]);
+
+    const [res2, err2] = erria(simpleSync);
+    console.log([res2, err2]);
+  };
+
+  start();
+```
+
+### Decorator
+
+```
+  import erria from 'erria/decorator';
+
+  class Foo {
+
+    @erria
+    async bar() : Promise<[any, Error] | any> {
+      const res = await simpleAsync(someParameter);
+      return res;
+    }
+  }
+
+  const start = async () => {
+    const foo = new Foo();
+    const [res3, err3] = await foo.bar();
+    console.log([res3, err3]);
+  };
+
+  start();
+```

test.ts

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+import erria from './index';
+import erriaDeco from './decorator';
+
+const simpleAsync = (something) => new Promise((resolve, reject) => {
+  setTimeout(() => {
+    console.log(something);
+    reject(new Error("Fail intentionally"))
+  }, 2000);
+});
+
+const simpleSync = () => {
+  const foo : any = {};
+  return foo.bar.failIntentionally();
+};
+
+class Foo {
+
+  @erriaDeco
+  async bar() : Promise<[any, Error] | any> {
+    const res = await simpleAsync(200);
+    return res;
+  }
+}
+
+const start = async () => {
+  const [res, err] = await erria(simpleAsync, 100);
+  console.log([res, err]);
+
+  const [res2, err2] = erria(simpleSync);
+  console.log([res2, err2]);
+
+  const foo = new Foo();
+  const [res3, err3] = await foo.bar();
+  console.log([res3, err3]);
+};
+
+start();

tsconfig.json

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+{
+  "compilerOptions": {
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": false,
+    "module": "commonjs",
+    "target": "es2017",
+    "sourceMap": true,
+    "experimentalDecorators": true
+  }
+}

yarn.lock

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+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+arg@^4.1.0:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/arg/-/arg-4.1.2.tgz#e70c90579e02c63d80e3ad4e31d8bfdb8bd50064"
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+
+buffer-from@^1.0.0:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/buffer-from/-/buffer-from-1.1.1.tgz#32713bc028f75c02fdb710d7c7bcec1f2c6070ef"
+  integrity sha512-MQcXEUbCKtEo7bhqEs6560Hyd4XaovZlO/k9V3hjVUF/zwW7KBVdSK4gIt/bzwS9MbR5qob+F5jusZsb0YQK2A==
+
+diff@^4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/diff/-/diff-4.0.1.tgz#0c667cb467ebbb5cea7f14f135cc2dba7780a8ff"
+  integrity sha512-s2+XdvhPCOF01LRQBC8hf4vhbVmI2CGS5aZnxLJlT5FtdhPCDFq80q++zK2KlrVorVDdL5BOGZ/VfLrVtYNF+Q==
+
+make-error@^1.1.1:
+  version "1.3.5"
+  resolved "https://registry.yarnpkg.com/make-error/-/make-error-1.3.5.tgz#efe4e81f6db28cadd605c70f29c831b58ef776c8"
+  integrity sha512-c3sIjNUow0+8swNwVpqoH4YCShKNFkMaw6oH1mNS2haDZQqkeZFlHS3dhoeEbKKmJB4vXpJucU6oH75aDYeE9g==
+
+source-map-support@^0.5.6:
+  version "0.5.16"
+  resolved "https://registry.yarnpkg.com/source-map-support/-/source-map-support-0.5.16.tgz#0ae069e7fe3ba7538c64c98515e35339eac5a042"
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+  dependencies:
+    buffer-from "^1.0.0"
+    source-map "^0.6.0"
+
+source-map@^0.6.0:
+  version "0.6.1"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
+  integrity sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==
+
+ts-node@^8.5.4:
+  version "8.5.4"
+  resolved "https://registry.yarnpkg.com/ts-node/-/ts-node-8.5.4.tgz#a152add11fa19c221d0b48962c210cf467262ab2"
+  integrity sha512-izbVCRV68EasEPQ8MSIGBNK9dc/4sYJJKYA+IarMQct1RtEot6Xp0bXuClsbUSnKpg50ho+aOAx8en5c+y4OFw==
+  dependencies:
+    arg "^4.1.0"
+    diff "^4.0.1"
+    make-error "^1.1.1"
+    source-map-support "^0.5.6"
+    yn "^3.0.0"
+
+typescript@^3.7.3:
+  version "3.7.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.7.3.tgz#b36840668a16458a7025b9eabfad11b66ab85c69"
+  integrity sha512-Mcr/Qk7hXqFBXMN7p7Lusj1ktCBydylfQM/FZCk5glCNQJrCUKPkMHdo9R0MTFWsC/4kPFvDS0fDPvukfCkFsw==
+
+yn@^3.0.0:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/yn/-/yn-3.1.1.tgz#1e87401a09d767c1d5eab26a6e4c185182d2eb50"
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