feat: tower effectiveness at range

* feat: tower effectiveness at range

* fix: supply the tower power in the function

Author: Arcath

src/tower-effectiveness-at-range/index.ts

@@ -0,0 +1,15 @@
+export function towerEffectivenessAtRange(
+	range: number,
+	max: number,
+): number {
+	if (range <= TOWER_OPTIMAL_RANGE) {
+		return max;
+ 	}
+	if (range >= TOWER_FALLOFF_RANGE) {
+		return max  * (1 - TOWER_FALLOFF);
+ 	}
+
+	const towerFalloffPerTile = TOWER_FALLOFF / (TOWER_FALLOFF_RANGE - TOWER_OPTIMAL_RANGE);
+
+	return max * (1 - (range - TOWER_OPTIMAL_RANGE) * towerFalloffPerTile);
+}

src/tower-effectiveness-at-range/package.json

@@ -0,0 +1,48 @@
+{
+  "name": "@open-screeps/tower-effectiveness-at-range",
+  "version": "0.0.0-development",
+  "description": "Calculate the effectiveness of tower actions at the given range",
+  "main": "index.js",
+  "scripts": {
+    "lint": "tslint -p ./tsconfig.json",
+    "test": "tsc && nyc ava",
+    "prepare": "npm test",
+    "release": "semantic-release -e semantic-release-monorepo"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/postcrafter/open-screeps.git"
+  },
+  "files": [
+    "index.{d.ts,js,js.map}"
+  ],
+  "keywords": [
+    "screeps",
+    "open-screeps"
+  ],
+  "author": "Adam Laycock <adam@arcath.net>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/postcrafter/open-screeps/issues"
+  },
+  "homepage": "https://github.com/postcrafter/open-screeps/src/tower-effectiveness-at-range#readme",
+  "dependencies": {
+    "@types/screeps": "^0.0.0"
+  },
+  "devDependencies": {
+    "ava": "^0.24.0",
+    "condition-circle": "^2.0.1",
+    "nyc": "^11.3.0",
+    "semantic-release": "^11.0.2",
+    "semantic-release-monorepo": "^4.0.0",
+    "tslint": "^5.9.1",
+    "tslint-config-airbnb": "^5.4.2",
+    "typescript": "^2.6.2"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "release": {
+    "verifyConditions": "condition-circle"
+  }
+}

src/tower-effectiveness-at-range/readme.md

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+# tower-effectiveness-at-range
+> Calculate the effectiveness of tower actions at the given range
+
+## Install
+```sh
+$ npm install @open-screeps/tower-effectiveness-at-range
+```
+
+## Usage
+```typescript
+import { towerEffectivenessAtRange } from '@open-screeps/tower-effectiveness-at-range';
+
+let damage = towerEffectivenessAtRange(creep.pos.getRangeTo(tower));
+
+let heal = towerEffectivenessAtRange(creep.pos.getRangeTo(tower), 'heal');
+
+let repair = towerEffectivenessAtRange(container.pos.getRangeTo(tower), 'repair');
+```
+
+## Related
+
+## License
+[MIT](../../license.md)

src/tower-effectiveness-at-range/test.ts

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+import ava from 'ava';
+
+import { towerEffectivenessAtRange } from './index';
+
+declare const global: any;
+
+global.TOWER_HITS = 3000;
+global.TOWER_CAPACITY = 1000;
+global.TOWER_ENERGY_COST = 10;
+global.TOWER_POWER_ATTACK = 600;
+global.TOWER_POWER_HEAL = 400;
+global.TOWER_POWER_REPAIR = 800;
+global.TOWER_OPTIMAL_RANGE = 5;
+global.TOWER_FALLOFF_RANGE = 20;
+global.TOWER_FALLOFF = 0.75;
+
+ava('Should calculate the tower effectiveness for the given ranges', (t) => {
+	t.is(towerEffectivenessAtRange(2, TOWER_POWER_ATTACK), 600);
+	t.is(towerEffectivenessAtRange(21, TOWER_POWER_ATTACK), 150);
+	t.is(towerEffectivenessAtRange(10, TOWER_POWER_ATTACK), 450);
+	t.is(towerEffectivenessAtRange(15, TOWER_POWER_ATTACK), 300);
+	t.is(towerEffectivenessAtRange(2, TOWER_POWER_HEAL), 400);
+	t.is(towerEffectivenessAtRange(2, TOWER_POWER_REPAIR), 800);
+});

src/tower-effectiveness-at-range/tsconfig.json

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+{
+  "extends": "../../tsconfig.base.json"
+}