diff --git a/src/JSONEditor.svelte b/src/JSONEditor.svelte
index d1f2e97..1fae384 100644
--- a/src/JSONEditor.svelte
+++ b/src/JSONEditor.svelte
@@ -17,7 +17,7 @@
   import Icon from 'svelte-awesome'
   import { faCut, faCopy, faPaste, faSearch, faUndo, faRedo } from '@fortawesome/free-solid-svg-icons'
   import { createHistory } from './history.js'
-  import Node from './JSONNode.svelte'
+  import JSONNode from './JSONNode.svelte'
   import { expandSelection } from './selection.js'
   import { isContentEditableDiv } from './utils/domUtils.js'
   import {
@@ -342,24 +342,17 @@
   }
 
   /**
-   * @param {Selection} newSelection
+   * @param {SelectionSchema} selectionSchema
    */
-  function handleSelect (newSelection) {
-    // TODO: refactor handleSelect: should be redundant except for the functionality to expand the selection and generate pathsMap
-
-    if (newSelection) {
-      const { paths, anchorPath, focusPath, beforePath, appendPath } = newSelection
+  function handleSelect (selectionSchema) {
+    if (selectionSchema) {
+      const { anchorPath, focusPath, beforePath, appendPath } = selectionSchema
 
       if (beforePath) {
-        selection = {
-          beforePath
-        }
+        selection = { beforePath }
       } else if (appendPath) {
-        selection = {
-          appendPath
-        }
+        selection = { appendPath }
       } else if (anchorPath && focusPath) {
-        // TODO: move expandSelection to JSONNode? (must change expandSelection to support relative path)
         const paths = expandSelection(doc, state, anchorPath, focusPath)
 
         selection = {
@@ -367,7 +360,7 @@
           pathsMap: createPathsMap(paths)
         }
       } else {
-        console.error('Unknown type of selection', newSelection)
+        console.error('Unknown type of selection', selectionSchema)
       }
 
       // set focus to the hidden input, so we can capture quick keys like Ctrl+X, Ctrl+C, Ctrl+V
@@ -552,7 +545,7 @@
     />
   </label>
   <div class="contents" bind:this={divContents}>
-    <Node
+    <JSONNode
       value={doc}
       path={[]}
       state={state}
diff --git a/src/operations.js b/src/operations.js
index aeb79e0..a783051 100644
--- a/src/operations.js
+++ b/src/operations.js
@@ -23,10 +23,10 @@ export function insertBefore (json, path, values, nextKeys) {  // TODO: find a b
   const parent = getIn(json, parentPath)
 
   if (Array.isArray(parent)) {
-    const startIndex = parseInt(last(path), 10)
-    return values.map((entry, offset) => ({
+    const offset = parseInt(last(path), 10)
+    return values.map((entry, index) => ({
       op: 'add',
-      path: compileJSONPointer(parentPath.concat(startIndex + offset)),
+      path: compileJSONPointer(parentPath.concat(offset + index)),
       value: entry.value
     }))
   }
@@ -65,10 +65,10 @@ export function append (json, path, values) {  // TODO: find a better name and d
   const parent = getIn(json, path)
 
   if (Array.isArray(parent)) {
-    const index = parent.length
-    return values.map((entry, offset) => ({
+    const offset = parent.length
+    return values.map((entry, index) => ({
       op: 'add',
-      path: compileJSONPointer(path.concat(index)),
+      path: compileJSONPointer(path.concat(offset + index)),
       value: entry.value
     }))
   }
diff --git a/src/selection.js b/src/selection.js
index 71f03c6..7a3a489 100644
--- a/src/selection.js
+++ b/src/selection.js
@@ -1,4 +1,4 @@
-import { isEqual } from 'lodash-es'
+import { first, initial, isEmpty, isEqual, last } from 'lodash-es'
 import { STATE_PROPS } from './constants.js'
 import { getIn } from './utils/immutabilityHelpers.js'
 import { isObject } from './utils/typeUtils.js'
@@ -11,7 +11,7 @@ import { isObject } from './utils/typeUtils.js'
  * @param {JSON} state
  * @param {Path} anchorPath
  * @param {Path} focusPath
- * @return {Path[]} selection
+ * @return {Path[]} paths
  */
 export function expandSelection (doc, state, anchorPath, focusPath) {
   if (isEqual(anchorPath, focusPath)) {
@@ -26,14 +26,14 @@ export function expandSelection (doc, state, anchorPath, focusPath) {
       return [ sharedPath ]
     }
 
-    const anchorProp = anchorPath[sharedPath.length]
-    const focusProp = focusPath[sharedPath.length]
+    const anchorKey = anchorPath[sharedPath.length]
+    const focusKey = focusPath[sharedPath.length]
     const value = getIn(doc, sharedPath)
 
     if (isObject(value)) {
       const props = getIn(state, sharedPath.concat(STATE_PROPS))
-      const anchorIndex = props.findIndex(prop => prop.key === anchorProp)
-      const focusIndex = props.findIndex(prop => prop.key === focusProp)
+      const anchorIndex = props.findIndex(prop => prop.key === anchorKey)
+      const focusIndex = props.findIndex(prop => prop.key === focusKey)
 
       if (anchorIndex !== -1 && focusIndex !== -1) {
         const startIndex = Math.min(anchorIndex, focusIndex)
@@ -49,8 +49,8 @@ export function expandSelection (doc, state, anchorPath, focusPath) {
     }
 
     if (Array.isArray(value)) {
-      const startIndex = Math.min(anchorProp, focusProp)
-      const endIndex = Math.max(anchorProp, focusProp)
+      const startIndex = Math.min(anchorKey, focusKey)
+      const endIndex = Math.max(anchorKey, focusKey)
       const paths = []
 
       for (let i = startIndex; i <= endIndex; i++) {
@@ -61,8 +61,7 @@ export function expandSelection (doc, state, anchorPath, focusPath) {
     }
   }
 
-  // should never happen
-  return []
+  throw new Error('Failed to create selection')
 }
 
 /**
diff --git a/src/types.js b/src/types.js
index 9530b3f..5ed3693 100644
--- a/src/types.js
+++ b/src/types.js
@@ -25,7 +25,7 @@
  */
 
 /**
- * @typedef {<string | number>[]} Path
+ * @typedef {Array<string | number>} Path
  */
 
 /**
@@ -50,5 +50,20 @@
  */
 
 /**
- * @typedef {{paths: Path[], pathsMap: Object<string, boolean>}} | {beforePath: Path} | {appendPath: Path}} Selection
+ * @typedef {{
+ *   paths: Path[],
+ *   pathsMap: Object<string, boolean>
+ * }} MultiSelection
+ *
+ * @typedef {{beforePath: Path}} BeforeSelection
+ *
+ * @typedef {{appendPath: Path}} AppendSelection
+
+ * @typedef {MultiSelection | BeforeSelection | AppendSelection} Selection
+ */
+
+/**
+ * @typedef {{anchorPath: Path, focusPath: Path}} MultiSelectionSchema
+ *
+ * @typedef {MultiSelectionSchema  | BeforeSelection | AppendSelection} SelectionSchema
  */