refactor: reduce code duplication in FloodFill (TheAlgorithms#1645)

* tests: add tests checking if floodFill funtions throw when location is outside * refactor: reduce code duplication by adding `checkLocation` to `FloodFill` * refactor: add and use `isInside` Co-authored-by: appgurueu <34514239+appgurueu@users.noreply.github.com> * Deduplicate further --------- Co-authored-by: appgurueu <34514239+appgurueu@users.noreply.github.com>

Author: vil02

Recursive/FloodFill.js

@@ -9,7 +9,7 @@
  * @see https://www.techiedelight.com/flood-fill-algorithm/
  */
 
-const neighbors = [
+const neighborOffsets = [
  [-1, -1],
  [-1, 0],
  [-1, 1],
@@ -20,6 +20,27 @@ const neighbors = [
  [1, 1]
 ]
 
+function isInside(rgbData, location) {
+ const x = location[0]
+ const y = location[1]
+ return x >= 0 && x < rgbData.length && y >= 0 && y < rgbData[0].length
+}
+
+function checkLocation(rgbData, location) {
+ if (!isInside(rgbData, location)) {
+ throw new Error('location should point to a pixel within the rgbData')
+ }
+}
+
+function* neighbors(rgbData, location) {
+ for (const offset of neighborOffsets) {
+ const neighborLocation = [location[0] + offset[0], location[1] + offset[1]]
+ if (isInside(rgbData, neighborLocation)) {
+ yield neighborLocation
+ }
+ }
+}
+
 /**
  * Implements the flood fill algorithm through a breadth-first approach using a queue.
  *
@@ -34,14 +55,7 @@ export function breadthFirstSearch(
  targetColor,
  replacementColor
 ) {
- if (
- location[0] < 0 ||
- location[0] >= rgbData.length ||
- location[1] < 0 ||
- location[1] >= rgbData[0].length
- ) {
- throw new Error('location should point to a pixel within the rgbData')
- }
+ checkLocation(rgbData, location)
 
  const queue = []
  queue.push(location)
@@ -65,14 +79,7 @@ export function depthFirstSearch(
  targetColor,
  replacementColor
 ) {
- if (
- location[0] < 0 ||
- location[0] >= rgbData.length ||
- location[1] < 0 ||
- location[1] >= rgbData[0].length
- ) {
- throw new Error('location should point to a pixel within the rgbData')
- }
+ checkLocation(rgbData, location)
 
  depthFirstFill(rgbData, location, targetColor, replacementColor)
 }
@@ -98,13 +105,8 @@ function breadthFirstFill(
 
  if (rgbData[currentLocation[0]][currentLocation[1]] === targetColor) {
  rgbData[currentLocation[0]][currentLocation[1]] = replacementColor
-
- for (let i = 0; i < neighbors.length; i++) {
- const x = currentLocation[0] + neighbors[i][0]
- const y = currentLocation[1] + neighbors[i][1]
- if (x >= 0 && x < rgbData.length && y >= 0 && y < rgbData[0].length) {
- queue.push([x, y])
- }
+ for (const neighborLocation of neighbors(rgbData, currentLocation)) {
+ queue.push(neighborLocation)
  }
  }
 }
@@ -120,13 +122,8 @@ function breadthFirstFill(
 function depthFirstFill(rgbData, location, targetColor, replacementColor) {
  if (rgbData[location[0]][location[1]] === targetColor) {
  rgbData[location[0]][location[1]] = replacementColor
-
- for (let i = 0; i < neighbors.length; i++) {
- const x = location[0] + neighbors[i][0]
- const y = location[1] + neighbors[i][1]
- if (x >= 0 && x < rgbData.length && y >= 0 && y < rgbData[0].length) {
- depthFirstFill(rgbData, [x, y], targetColor, replacementColor)
- }
+ for (const neighborLocation of neighbors(rgbData, location)) {
+ depthFirstFill(rgbData, neighborLocation, targetColor, replacementColor)
  }
  }
 }

Recursive/test/FloodFill.test.js

@@ -21,6 +21,19 @@ describe('FloodFill', () => {
  })
 })
 
+describe.each([breadthFirstSearch, depthFirstSearch])('%o', (floodFillFun) => {
+ it.each([
+ [1, -1],
+ [-1, 1],
+ [0, 7],
+ [7, 0]
+ ])('throws for start position [%i, %i]', (location) => {
+ expect(() =>
+ floodFillFun(generateTestRgbData(), location, green, orange)
+ ).toThrowError()
+ })
+})
+
 /**
  * Utility-function to test the function "breadthFirstSearch".
  *