Add types for decay (#13982)

Add an optional extended description…

decay/decay-tests.ts

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+import {redditHot, hackerHot, wilsonScore} from 'decay';
+
+const upvotes = 42;
+const downvotes = 12;
+const posted = new Date(2017, 1, 1);
+
+let score: number;
+
+let redditCalculator = redditHot();
+score = redditCalculator(upvotes, downvotes, posted);
+redditCalculator = redditHot(10000);
+score = redditCalculator(upvotes, downvotes, posted);
+
+let hackerCalculator = hackerHot();
+score = hackerCalculator(upvotes, posted);
+hackerCalculator = hackerHot(1.6);
+score = hackerCalculator(upvotes, posted);
+
+let wilsonCalculator = wilsonScore();
+score = wilsonCalculator(upvotes, downvotes);
+wilsonCalculator = wilsonScore(1.0);
+score = wilsonCalculator(upvotes, downvotes);

decay/index.d.ts

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+// Type definitions for decay 1.0
+// Project: https://github.com/clux/decay
+// Definitions by: Eric Naeseth <https://github.com/enaeseth>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+/**
+ * Creates a function to rank posts using Reddit's "hot" algorithm.
+ * @param decay controls how quickly rankings drop with time
+ * @return calculator function
+ */
+export function redditHot(decay?: number): RedditHotFunction;
+
+/**
+ * Creates a function to rank posts using the Hacker News "hot" algorithm.
+ * @param gravity controls how quickly rankings drop with time
+ * @return calculator function
+ */
+export function hackerHot(gravity?: number): HackerNewsHotFunction;
+
+/**
+ * Creates a function to rank posts using the Wilson score interval sort (Reddit's "best"
+ * algorithm).
+ * @param confidence statistical confidence
+ * @return calculator function
+ * @see {@link https://redditblog.com/2009/10/15/reddits-new-comment-sorting-system/ Reddit's writeup}
+ */
+export function wilsonScore(confidence?: number): WilsonScoreFunction;
+
+/**
+ * Computes a ranking using Reddit's "hot" algorithm.
+ * @param upvotes number of upvotes the post has received
+ * @param downvotes number of upvotes the post has received
+ * @param date when the post was posted
+ * @return ranking
+ */
+export type RedditHotFunction = (upvotes: number, downvotes: number, date: Date) => number;
+
+/**
+ * Computes a ranking using the Hacker News "hot" algorithm.
+ * @param votes number of upvotes the post has received
+ * @param date when the post was posted
+ * @return ranking
+ */
+export type HackerNewsHotFunction = (votes: number, date: Date) => number;
+
+/**
+ * Computes a ranking using the Wilson score (Reddit's "best" algorithm).
+ * @param upvotes number of upvotes the post has received
+ * @param downvotes number of upvotes the post has received
+ * @return ranking
+ */
+export type WilsonScoreFunction = (upvotes: number, downvotes: number) => number;

decay/tsconfig.json

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+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "target": "es6",
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "decay-tests.ts"
+    ]
+}

decay/tslint.json

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+{ "extends": "../tslint.json" }