feat: using browser field for browsers environment

Author: AuHau

README.md

@@ -173,28 +173,35 @@ Each migration must follow this API. It must export an object in its `index.js`
  * `migrate` (function) - Function that performs the migration (see signature of this function below)
  * `revert` (function) - If defined then this function will revert the migration to the previous version. Otherwise it is assumed that it is not possible to revert this migration.
 
-#### `.migrate(repoPath, repoOptions, isBrowser)`
+#### `.migrate(repoPath, repoOptions)`
 
 _Do not confuse this function with the `require('ipfs-repo-migrations').migrate()` function that drives the whole migration process!_
 
 Arguments:
  * `repoPath` (string) - absolute path to the root of the repo
  * `repoOptions` (object, optional) - object containing `IPFSRepo` options, that should be used to construct a datastore instance.
- * `isBrowser` (bool) - indicates if the migration is run in a browser environment (as opposed to NodeJS)
 
-#### `.revert(repoPath, repoOptions, isBrowser)`
+#### `.revert(repoPath, repoOptions)`
 
 _Do not confuse this function with the `require('ipfs-repo-migrations').revert()` function that drives the whole backward migration process!_
 
 Arguments:
  * `repoPath` (string) - path to the root of the repo
  * `repoOptions` (object, optional) - object containing `IPFSRepo` options, that should be used to construct the datastore instance.
- * `isBrowser` (bool) - indicates if the migration is run in a browser environment (as opposed to NodeJS)
 
 ### Browser vs. NodeJS environments
 
-The migration might need to distinguish in which environment it runs (browser vs. NodeJS). For this reason there is an argument
-`isBrowser` passed to migrations functions. But with simple migrations it should not be necessary to distinguish between
+The migration might need to perform specific tasks in browser or NodeJS environment. In such a case create
+migration file `/migrations/migration-<number>/index_browser.js` which have to follow the same API is described before.
+Then add entry in `package.json` to the `browser` field as follow:
+
+```
+'./migrations/migration-<number>/index.js': './migrations/migration-<number>/index_browser.js'
+```
+
+In browser environments then `index.js` will be replaced with `index_browser.js`.
+
+Simple migrations should not need to distinguish between
 these environments as the datastore implementation will handle the main differences. 
 
 There are currently two main datastore implementations:

package.json

@@ -49,7 +49,6 @@
     "datastore-level": "~0.12.1",
     "debug": "^4.1.0",
     "interface-datastore": "~0.8.0",
-    "is-electron": "^2.2.0",
     "proper-lockfile": "^4.1.1",
     "yargs": "^14.2.0",
     "yargs-promise": "^1.1.0"

src/index.js

@@ -4,11 +4,6 @@ const defaultMigrations = require('../migrations')
 const repoVersion = require('./repo/version')
 const repoLock = require('./repo/lock')
 const errors = require('./errors')
-const isElectron = require('is-electron')
-
-const IS_ENV_WITH_DOM = typeof window === 'object' && typeof document === 'object' && document.nodeType === 9
-const IS_ELECTRON = isElectron()
-const IS_BROWSER = IS_ENV_WITH_DOM && !IS_ELECTRON
 
 const log = require('debug')('repo-migrations:migrator')
 
@@ -98,7 +93,7 @@ async function migrate (path, toVersion, { ignoreLock = false, repoOptions, onPr
       counter++
       log(`Migrating version ${migration.version}`)
       try {
-        if (!isDryRun) await migration.migrate(path, repoOptions, IS_BROWSER)
+        if (!isDryRun) await migration.migrate(path, repoOptions)
       } catch (e) {
         const lastSuccessfullyMigratedVersion = migration.version - 1
         log(`An exception was raised during execution of migration. Setting the repo's version to last successfully migrated version: ${lastSuccessfullyMigratedVersion}`)
@@ -188,7 +183,7 @@ async function revert (path, toVersion, { ignoreLock = false, repoOptions, onPro
       counter++
       log(`Reverting migration version ${migration.version}`)
       try {
-        if (!isDryRun) await migration.revert(path, repoOptions, IS_BROWSER)
+        if (!isDryRun) await migration.revert(path, repoOptions)
       } catch (e) {
         const lastSuccessfullyRevertedVersion = migration.version
         log(`An exception was raised during execution of migration. Setting the repo's version to last successfully reverted version: ${lastSuccessfullyRevertedVersion}`)