Adopt type=module

.eslintrc.json

@@ -5,9 +5,7 @@
     "ecmaVersion": 8
   },
   "env": {
-    "es6": true,
-    "node": true,
-    "browser": true
+    "es6": true
   },
   "rules": {
     "no-cond-assign": 0

.github/eslint.json

@@ -0,0 +1,18 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "eslint-compact",
+      "pattern": [
+        {
+          "regexp": "^(.+):\\sline\\s(\\d+),\\scol\\s(\\d+),\\s(Error|Warning|Info)\\s-\\s(.+)\\s\\((.+)\\)$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "severity": 4,
+          "message": 5,
+          "code": 6
+        }
+      ]
+    }
+  ]
+}

.github/workflows/node.js.yml

@@ -0,0 +1,30 @@
+# https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
+
+name: Node.js CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [14.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: yarn --frozen-lockfile
+    - run: |
+        echo ::add-matcher::.github/eslint.json
+        yarn run eslint src test --format=compact
+    - run: yarn test

LICENSE

@@ -1,58 +1,13 @@
-Copyright (c) 2010-2015, Michael Bostock
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-* Redistributions of source code must retain the above copyright notice, this
-  list of conditions and the following disclaimer.
-
-* Redistributions in binary form must reproduce the above copyright notice,
-  this list of conditions and the following disclaimer in the documentation
-  and/or other materials provided with the distribution.
-
-* The name Michael Bostock may not be used to endorse or promote products
-  derived from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL MICHAEL BOSTOCK BE LIABLE FOR ANY DIRECT,
-INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
-BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
-OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
-EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-TERMS OF USE - EASING EQUATIONS
-
-Open source under the BSD License.
-
-Copyright 2001 Robert Penner
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without modification,
-are permitted provided that the following conditions are met:
-
-- Redistributions of source code must retain the above copyright notice, this
-  list of conditions and the following disclaimer.
-
-- Redistributions in binary form must reproduce the above copyright notice,
-  this list of conditions and the following disclaimer in the documentation
-  and/or other materials provided with the distribution.
-
-- Neither the name of the author nor the names of contributors may be used to
-  endorse or promote products derived from this software without specific prior
-  written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
-ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
-ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+Copyright 2010-2021 Mike Bostock
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+THIS SOFTWARE.

README.md

@@ -16,24 +16,36 @@ To compute intermediate state, transitions leverage a variety of [built-in inter
 
 ## Installing
 
-If you use NPM, `npm install d3-transition`. Otherwise, download the [latest release](https://github.com/d3/d3-transition/releases/latest). You can also load directly from [d3js.org](https://d3js.org), either as a [standalone library](https://d3js.org/d3-transition.v2.min.js) or as part of [D3](https://github.com/d3/d3). AMD, CommonJS, and vanilla environments are supported. In vanilla, a `d3` global is exported:
+If you use npm, `npm install d3-transition`. You can also download the [latest release on GitHub](https://github.com/d3/d3-transition/releases/latest). For vanilla HTML in modern browsers, import d3-transition from Skypack:
 
 ```html
-<script src="https://d3js.org/d3-color.v2.min.js"></script>
-<script src="https://d3js.org/d3-dispatch.v2.min.js"></script>
-<script src="https://d3js.org/d3-ease.v2.min.js"></script>
-<script src="https://d3js.org/d3-interpolate.v2.min.js"></script>
-<script src="https://d3js.org/d3-selection.v2.min.js"></script>
-<script src="https://d3js.org/d3-timer.v2.min.js"></script>
-<script src="https://d3js.org/d3-transition.v2.min.js"></script>
+<script type="module">
+
+import {transition} from "https://cdn.skypack.dev/d3-transition@3";
+
+const t = transition();
+
+</script>
+```
+
+For legacy environments, you can load d3-transition’s UMD bundle from an npm-based CDN such as jsDelivr; a `d3` global is exported:
+
+```html
+<script src="https://cdn.jsdelivr.net/npm/d3-color@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/d3-dispatch@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/d3-ease@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/d3-interpolate@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/d3-selection@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/d3-timer@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/d3-transition@3"></script>
 <script>
 
-var transition = d3.transition();
+const t = d3.transition();
 
 </script>
 ```
 
-[Try d3-transition in your browser.](https://tonicdev.com/npm/d3-transition)
+[Try d3-transition in your browser.](https://observablehq.com/collection/@d3/d3-transition)
 
 ## API Reference
 
@@ -296,7 +308,7 @@ For each selected element, sets the [text content](http://www.w3.org/TR/DOM-Leve
 To interpolate text rather than to set it on start, use [*transition*.textTween](#transition_textTween) or append a replacement element and cross-fade opacity. Text is not interpolated by default because it is usually undesirable.
 
 <a name="transition_textTween" href="#transition_textTween">#</a> <i>transition</i>.<b>textTween</b>(<i>factory</i>) · [Source](https://github.com/d3/d3-transition/blob/master/src/transition/textTween.js), [Examples](https://observablehq.com/@d3/transition-texttween)
- 
+
 If *factory* is specified and not null, assigns the text [tween](#transition_tween) to the specified interpolator *factory*. An interpolator factory is a function that returns an [interpolator](https://github.com/d3/d3-interpolate); when the transition starts, the *factory* is evaluated for each selected element, in order, being passed the current datum `d` and index `i`, with the `this` context as the current DOM element. The returned interpolator will then be invoked for each frame of the transition, in order, being passed the [eased](#transition_ease) time *t*, typically in the range [0, 1]. Lastly, the return value of the interpolator will be used to set the text. The interpolator must return a string.
 
 For example, to interpolate the text with integers from 0 to 100:

package.json

@@ -2,54 +2,61 @@
   "name": "d3-transition",
   "version": "2.0.0",
   "description": "Animated transitions for D3 selections.",
+  "homepage": "https://d3js.org/d3-transition/",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/d3/d3-transition.git"
+  },
   "keywords": [
     "d3",
     "d3-module",
     "dom",
     "transition",
     "animation"
   ],
-  "homepage": "https://d3js.org/d3-transition/",
-  "license": "BSD-3-Clause",
+  "license": "ISC",
   "author": {
     "name": "Mike Bostock",
     "url": "https://bost.ocks.org/mike"
   },
-  "main": "dist/d3-transition.js",
-  "unpkg": "dist/d3-transition.min.js",
-  "jsdelivr": "dist/d3-transition.min.js",
-  "module": "src/index.js",
-  "repository": {
-    "type": "git",
-    "url": "https://github.com/d3/d3-transition.git"
-  },
+  "type": "module",
   "files": [
     "dist/**/*.js",
     "src/**/*.js"
   ],
-  "scripts": {
-    "pretest": "rollup -c",
-    "test": "tape 'test/**/*-test.js' && eslint src",
-    "prepublishOnly": "rm -rf dist && yarn test",
-    "postpublish": "git push && git push --tags && cd ../d3.github.com && git pull && cp ../${npm_package_name}/dist/${npm_package_name}.js ${npm_package_name}.v${npm_package_version%%.*}.js && cp ../${npm_package_name}/dist/${npm_package_name}.min.js ${npm_package_name}.v${npm_package_version%%.*}.min.js && git add ${npm_package_name}.v${npm_package_version%%.*}.js ${npm_package_name}.v${npm_package_version%%.*}.min.js && git commit -m \"${npm_package_name} ${npm_package_version}\" && git push && cd - && zip -j dist/${npm_package_name}.zip -- LICENSE README.md dist/${npm_package_name}.js dist/${npm_package_name}.min.js"
+  "module": "src/index.js",
+  "main": "src/index.js",
+  "jsdelivr": "dist/d3-transition.min.js",
+  "unpkg": "dist/d3-transition.min.js",
+  "exports": {
+    "umd": "./dist/d3-transition.min.js",
+    "default": "./src/index.js"
   },
   "sideEffects": true,
   "dependencies": {
-    "d3-color": "1 - 2",
-    "d3-dispatch": "1 - 2",
-    "d3-ease": "1 - 2",
-    "d3-interpolate": "1 - 2",
-    "d3-timer": "1 - 2"
+    "d3-color": "1 - 3",
+    "d3-dispatch": "1 - 3",
+    "d3-ease": "1 - 3",
+    "d3-interpolate": "1 - 3",
+    "d3-timer": "1 - 3"
+  },
+  "devDependencies": {
+    "d3-selection": "2 - 3",
+    "eslint": "7",
+    "jsdom": "16",
+    "mocha": "9",
+    "rollup": "2",
+    "rollup-plugin-terser": "7"
+  },
+  "scripts": {
+    "test": "mocha 'test/**/*-test.js' && eslint src test",
+    "prepublishOnly": "rm -rf dist && yarn test && rollup -c",
+    "postpublish": "git push && git push --tags && cd ../d3.github.com && git pull && cp ../${npm_package_name}/dist/${npm_package_name}.js ${npm_package_name}.v${npm_package_version%%.*}.js && cp ../${npm_package_name}/dist/${npm_package_name}.min.js ${npm_package_name}.v${npm_package_version%%.*}.min.js && git add ${npm_package_name}.v${npm_package_version%%.*}.js ${npm_package_name}.v${npm_package_version%%.*}.min.js && git commit -m \"${npm_package_name} ${npm_package_version}\" && git push && cd -"
+  },
+  "engines": {
+    "node": ">=12"
   },
   "peerDependencies": {
     "d3-selection": "2"
-  },
-  "devDependencies": {
-    "d3-selection": "2",
-    "eslint": "6",
-    "jsdom": "15",
-    "rollup": "1",
-    "rollup-plugin-terser": "5",
-    "tape": "4"
   }
 }

rollup.config.js

@@ -1,6 +1,14 @@
+import {readFileSync} from "fs";
 import {terser} from "rollup-plugin-terser";
 import * as meta from "./package.json";
 
+// Extract copyrights from the LICENSE.
+const copyright = readFileSync("./LICENSE", "utf-8")
+  .split(/\n/g)
+  .filter(line => /^Copyright\s+/.test(line))
+  .map(line => line.replace(/^Copyright\s+/, ""))
+  .join(", ");
+
 const config = {
   input: "src/index.js",
   external: Object.keys(meta.dependencies || {}).filter(key => /^d3-/.test(key)),
@@ -10,7 +18,7 @@ const config = {
     format: "umd",
     indent: false,
     extend: true,
-    banner: `// ${meta.homepage} v${meta.version} Copyright ${(new Date).getFullYear()} ${meta.author.name}`,
+    banner: `// ${meta.homepage} v${meta.version} Copyright ${copyright}`,
     globals: Object.assign({}, ...Object.keys({...meta.dependencies, ...meta.peerDependencies}).filter(key => /^d3-/.test(key)).map(key => ({[key]: "d3"})))
   },
   plugins: [],

test/.eslintrc.json

@@ -0,0 +1,13 @@
+{
+  "extends": "eslint:recommended",
+  "parserOptions": {
+    "sourceType": "module",
+    "ecmaVersion": 8
+  },
+  "env": {
+    "mocha": true,
+    "node": true,
+    "es6": true,
+    "browser": true
+  }
+}