Initial release.

index.js

@@ -0,0 +1,52 @@
+function getPath(zip) {
+  return zip.split('').map((x) => parseInt(x));
+}
+
+let zipTree = null;
+function getByZipCode(zip) {
+  if (zipTree === null) {
+    zipTree = require('./zip-tree.json');
+  }
+  const p = getPath(zip + '');
+  return zipTree[p[0]] && zipTree[p[0]][p[1]] && zipTree[p[0]][p[1]][p[2]] && zipTree[p[0]][p[1]][p[2]][p[3]] && zipTree[p[0]][p[1]][p[2]][p[3]][p[4]]
+    ? zipTree[p[0]][p[1]][p[2]][p[3]][p[4]]
+    : null;
+}
+
+let locTree = null;
+function distance(lat, long, op) {
+  return Math.pow(lat - op.lat, 2) + Math.pow(long - op.long, 2);
+}
+function getByLocation(lat, long) {
+  if (locTree === null) {
+    locTree = require('./loc-tree.json');
+  }
+  let latPath  = Math.floor(Math.abs(lat)  * 10);
+  let longPath = Math.floor(Math.abs(long) * 10);
+  if (longPath < 1000) {
+    longPath = '0' + longPath;
+  }
+  const p = getPath(latPath + '' + longPath);
+  let curr = locTree.points;
+  for (let i = 0; i < p.length; i++) {
+    if (!curr[p[i]]) {
+      return null;
+    }
+    curr = curr[p[i]];
+  }
+  let d = distance(lat, long, locTree.index[curr[0]]);
+  let index = 0;
+  for (let i = 1; i < curr.length; i++) {
+    let nd = distance(lat, long, locTree.index[curr[i]]);
+    if (nd < d) {
+      d = nd;
+      index = i;
+    }
+  }
+  return locTree.index[curr[index]];
+}
+
+module.exports = {
+  getByLocation: getByLocation,
+  getByZipCode: getByZipCode
+};

package.json

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+{
+  "name": "zips",
+  "version": "1.0.0",
+  "description": "Light, fast, tree-based way to get cities by zipcode and location.",
+  "main": "index.js",
+  "scripts": {
+    "test": "node test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/crhallberg/zips.git"
+  },
+  "keywords": [
+    "zipcodes",
+    "zip",
+    "code",
+    "geo",
+    "zipcode",
+    "postal",
+    "code"
+  ],
+  "author": "Chris Hallberg",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/crhallberg/zips/issues"
+  },
+  "homepage": "https://github.com/crhallberg/zips#readme"
+}

test.js

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+function toMillis(start) {
+  return Math.round(process.hrtime(start)[1] / 1e3) / 1e3;
+}
+
+const library = require('./index');
+// Zip code
+let start = process.hrtime();
+library.getByZipCode('08848');
+console.log('by zip - cold', toMillis(start), 'ms');
+let avgStart = process.hrtime();
+for (let i = 0; i < 5; i++) {
+  start = process.hrtime();
+  library.getByZipCode('19085');
+  console.log('by zip - warm', toMillis(start), 'ms');
+  start = process.hrtime();
+  library.getByZipCode('19026');
+  console.log('by zip - warm', toMillis(start), 'ms');
+}
+console.log('by zip warm avg', toMillis(avgStart) / 10, 'ms');
+console.log();
+
+// Location
+start = process.hrtime();
+library.getByLocation(40.5929, -75.1025);
+console.log('by loc - cold', toMillis(start), 'ms');
+avgStart = process.hrtime();
+for (let i = 0; i < 5; i++) {
+  start = process.hrtime();
+  library.getByLocation(40.0399, -75.3459);
+  console.log('by loc - warm', toMillis(start), 'ms');
+  start = process.hrtime();
+  library.getByLocation(39.9503, -75.304);
+  console.log('by loc - warm', toMillis(start), 'ms');
+}
+console.log('by loc warm avg', toMillis(avgStart) / 10, 'ms');