diff --git a/githooks/build-minidex b/githooks/build-minidex
new file mode 100755
index 000000000..e8ecb2a1d
--- /dev/null
+++ b/githooks/build-minidex
@@ -0,0 +1,50 @@
+#!/usr/bin/env node
+'use strict';
+
+const fs = require("fs");
+process.chdir(__dirname);
+const imageSize = require('image-size');
+
+const Tools = require('./../data/Pokemon-Showdown/tools').includeData();
+const toId = Tools.getId;
+
+let buf = `/*
+DO NOT EDIT
+
+THIS FILE IS AUTOGENERATED BY ./githooks/build-minidex
+*/
+
+exports.BattlePokemonSprites = {
+	substitute:{exists:false, front:{ani:{w:34, h:39}}, back:{ani:{w:37, h:38}}},
+`;
+for (let id in Tools.data.Pokedex) {
+	let template = Tools.getTemplate(id);
+	let row = {num: template.num};
+	try {
+		let size = imageSize('../sprites/xyani/' + template.spriteid + '.gif');
+		row.front = {
+			ani: {
+				w: size.width,
+				h: size.height
+			}
+		};
+	} catch (e) {}
+	try {
+		let size = imageSize('../sprites/xyani-back/' + template.spriteid + '.gif');
+		row.back = {
+			ani: {
+				w: size.width,
+				h: size.height
+			}
+		};
+	} catch (e) {}
+	if (row.num <= 0 || row.front || row.back || !row.forme) {
+		buf += `\t${id}:` + JSON.stringify(row).replace(/"/g, '') + `,\n`;
+	}
+}
+
+buf = buf.slice(0, -2) + `
+};
+`;
+
+fs.writeFileSync('../data/pokedex-mini.js', buf);