Implement CSV Grain Integration Plugin (#3078)

This plugin outputs a csv file. Each row contains a payout address in
the first column and the raw amount to be paid in the second column.

The file content is returned to SourceCred, which will handle file I/O
on behalf of plugins.

grain integrations shall be prefixed in their package.json files with
`sc-grainIntegration-*` this will allow for grouping and filtering using
lerna and allow for a clean change in the scope of concerns.

The output is optimized for https://disperse.app

test plan: unit tests are provided

.gitignore

@@ -2,7 +2,7 @@
 
 # dependencies
 /node_modules
-
+**/node_modules
 # testing
 /coverage
 
@@ -27,5 +27,5 @@
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+lerna-debug.log
 .DS_Store
-

packages/grainIntegration-csv/.babelrc.js

@@ -0,0 +1,19 @@
+// @flow
+
+const presets = [
+  [
+    "@babel/preset-env",
+    {
+      targets: {
+        edge: "17",
+        firefox: "60",
+        chrome: "67",
+        safari: "11.1",
+        node: true,
+      },
+    },
+  ],
+  "@babel/preset-flow",
+];
+
+module.exports = { presets };

packages/grainIntegration-csv/.eslintrc.js

@@ -0,0 +1,55 @@
+// @flow
+module.exports = {
+  parser: "babel-eslint",
+  plugins: ["flowtype", "react"],
+  env: {
+    browser: true,
+    es6: true,
+    node: true,
+    jest: true,
+  },
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: "module",
+    ecmaFeatures: {
+      jsx: true,
+    },
+  },
+  extends: [
+    "eslint:recommended",
+    "plugin:react/recommended",
+    "plugin:flowtype/recommended",
+  ],
+  rules: {
+    "prefer-const": ["warn"],
+    camelcase: [
+      "error",
+      {properties: "never", allow: ["^_unused_.*", "(_\\d+)+"]},
+    ],
+    eqeqeq: ["error", "always", {null: "ignore"}],
+    "no-unused-vars": [
+      "warn",
+      {
+        argsIgnorePattern: "^_$|^_unused_",
+        varsIgnorePattern: "^_$|^_unused_",
+        caughtErrorsIgnorePattern: "^_$|^_unused_",
+      },
+    ],
+    "no-constant-condition": ["warn", {checkLoops: false}],
+    "no-inner-declarations": ["off"],
+    "no-use-before-define": ["off"],
+    "no-useless-constructor": ["off"],
+    "no-case-declarations": ["off"],
+    "react/prop-types": ["off"],
+    "flowtype/generic-spacing": ["off"],
+    "flowtype/space-after-type-colon": ["off"],
+  },
+  settings: {
+    react: {
+      version: "detect",
+    },
+  },
+  globals: {
+    BigInt: "readonly",
+  },
+};

packages/grainIntegration-csv/.flowconfig

@@ -0,0 +1,14 @@
+# If modifying this file, please modify .flowconfig-ci too!
+[ignore]
+
+[include]
+
+[libs]
+flow-typed
+
+[lints]
+
+[options]
+include_warnings=true
+
+[strict]

packages/grainIntegration-csv/.flowconfig-ci

@@ -0,0 +1,16 @@
+# If modifying this file, please modify .flowconfig too!
+[ignore]
+
+[include]
+
+[libs]
+flow-typed
+
+[lints]
+
+[options]
+include_warnings=true
+server.max_workers=1
+types_first=false
+
+[strict]

packages/grainIntegration-csv/distributionToCsv.js

@@ -0,0 +1,12 @@
+// @flow
+
+/*:: type PayoutDistributions = $ReadOnlyArray<[string, string]>;*/
+module.exports = function payoutDistributionToCsv(
+  payoutDistributions /*: PayoutDistributions*/
+) /*: string*/ {
+  let csvString = "";
+  for (const [payoutAddress, amount] of payoutDistributions) {
+    csvString += `${payoutAddress},${amount}\n`;
+  }
+  return csvString;
+};