Initial code test

node_modules/dotenv-expand/lib/main.js

@@ -0,0 +1,98 @@
+'use strict'
+
+function _resolveEscapeSequences (value) {
+  return value.replace(/\\\$/g, '$')
+}
+
+function expandValue (value, processEnv, runningParsed) {
+  const env = { ...runningParsed, ...processEnv } // process.env wins
+
+  const regex = /(?<!\\)\${([^{}]+)}|(?<!\\)\$([A-Za-z_][A-Za-z0-9_]*)/g
+
+  let result = value
+  let match
+  const seen = new Set() // self-referential checker
+
+  while ((match = regex.exec(result)) !== null) {
+    seen.add(result)
+
+    const [template, bracedExpression, unbracedExpression] = match
+    const expression = bracedExpression || unbracedExpression
+
+    // match the operators `:+`, `+`, `:-`, and `-`
+    const opRegex = /(:\+|\+|:-|-)/
+    // find first match
+    const opMatch = expression.match(opRegex)
+    const splitter = opMatch ? opMatch[0] : null
+
+    const r = expression.split(splitter)
+
+    let defaultValue
+    let value
+
+    const key = r.shift()
+
+    if ([':+', '+'].includes(splitter)) {
+      defaultValue = env[key] ? r.join(splitter) : ''
+      value = null
+    } else {
+      defaultValue = r.join(splitter)
+      value = env[key]
+    }
+
+    if (value) {
+      // self-referential check
+      if (seen.has(value)) {
+        result = result.replace(template, defaultValue)
+      } else {
+        result = result.replace(template, value)
+      }
+    } else {
+      result = result.replace(template, defaultValue)
+    }
+
+    // if the result equaled what was in process.env and runningParsed then stop expanding
+    if (result === runningParsed[key]) {
+      break
+    }
+
+    regex.lastIndex = 0 // reset regex search position to re-evaluate after each replacement
+  }
+
+  return result
+}
+
+function expand (options) {
+  // for use with progressive expansion
+  const runningParsed = {}
+
+  let processEnv = process.env
+  if (options && options.processEnv != null) {
+    processEnv = options.processEnv
+  }
+
+  // dotenv.config() ran before this so the assumption is process.env has already been set
+  for (const key in options.parsed) {
+    let value = options.parsed[key]
+
+    // short-circuit scenario: process.env was already set prior to the file value
+    if (processEnv[key] && processEnv[key] !== value) {
+      value = processEnv[key]
+    } else {
+      value = expandValue(value, processEnv, runningParsed)
+    }
+
+    options.parsed[key] = _resolveEscapeSequences(value)
+
+    // for use with progressive expansion
+    runningParsed[key] = _resolveEscapeSequences(value)
+  }
+
+  for (const processKey in options.parsed) {
+    processEnv[processKey] = options.parsed[processKey]
+  }
+
+  return options
+}
+
+module.exports.expand = expand