Bring back isPluginRequired (#9709)

packages/babel-preset-env/src/index.js

@@ -20,6 +20,8 @@ import availablePlugins from "./available-plugins";
 import { filterStageFromList, prettifyTargets } from "./utils";
 import { declare } from "@babel/helper-plugin-utils";
 
+export { isPluginRequired } from "./filter-items";
+
 const pluginListWithoutProposals = filterStageFromList(
   pluginList,
   proposalPlugins,

packages/babel-preset-env/test/is-plugin-required.js

@@ -0,0 +1,82 @@
+"use strict";
+
+const presetEnv = require("../");
+
+describe("isPluginRequired", () => {
+  const MAX_VERSION = `${Number.MAX_SAFE_INTEGER}.0.0`;
+
+  it("returns true if no targets are specified", () => {
+    expect(presetEnv.isPluginRequired({}, {})).toBe(true);
+  });
+
+  it("returns true if plugin feature is not implemented in one or more targets", () => {
+    let targets;
+    const plugin = {
+      edge: false,
+      firefox: 45,
+      chrome: 49,
+    };
+
+    targets = {
+      chrome: MAX_VERSION,
+      firefox: MAX_VERSION,
+    };
+    expect(presetEnv.isPluginRequired(targets, plugin)).toBe(false);
+
+    targets = {
+      edge: "12",
+    };
+    expect(presetEnv.isPluginRequired(targets, plugin)).toBe(true);
+  });
+
+  it("returns false if plugin feature is implemented by lower than target", () => {
+    const plugin = {
+      chrome: 49,
+    };
+    const targets = {
+      chrome: MAX_VERSION,
+    };
+
+    expect(presetEnv.isPluginRequired(targets, plugin)).toBe(false);
+  });
+
+  it("returns false if plugin feature is implemented is equal to target", () => {
+    const plugin = {
+      chrome: 49,
+    };
+    const targets = {
+      chrome: "49.0.0",
+    };
+    expect(presetEnv.isPluginRequired(targets, plugin)).toBe(false);
+  });
+
+  it("returns true if plugin feature is implemented is greater than target", () => {
+    const plugin = {
+      chrome: 50,
+    };
+    const targets = {
+      chrome: "49.0.0",
+    };
+    expect(presetEnv.isPluginRequired(targets, plugin)).toBe(true);
+  });
+
+  it("returns when target is a decimal", () => {
+    const plugin = {
+      node: 6.9,
+    };
+    const targets = {
+      node: "6.10.0",
+    };
+    expect(presetEnv.isPluginRequired(targets, plugin)).toBe(false);
+  });
+
+  it("throws an error if target version is invalid", () => {
+    const plugin = {
+      chrome: 50,
+    };
+    const targets = {
+      chrome: 55,
+    };
+    expect(() => presetEnv.isPluginRequired(targets, plugin)).toThrow();
+  });
+});