How to use @babel/plugin-proposal-optional-chaining - 8 common examples
To help you get started, we’ve selected a few @babel/plugin-proposal-optional-chaining examples, based on popular ways it is used in public projects.
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facebook / metro / packages / metro-babel-register / src / babel-register.js View on Github 
'use strict';
const escapeRegExp = require('escape-string-regexp');
const path = require('path');
require('./node-polyfills');
var _only = [];
const PLUGINS = [
[require('@babel/plugin-transform-flow-strip-types').default],
[require('@babel/plugin-proposal-object-rest-spread').default],
[require('@babel/plugin-proposal-class-properties').default],
[require('@babel/plugin-transform-modules-commonjs').default],
[require('@babel/plugin-proposal-nullish-coalescing-operator').default],
[require('@babel/plugin-proposal-optional-catch-binding').default],
[require('@babel/plugin-proposal-optional-chaining').default],
];
if (/^v[0-7]\./.test(process.version)) {
PLUGINS.push([require('@babel/plugin-transform-async-to-generator').default]);
}
function registerOnly(onlyList) {
// This prevents `babel-register` from transforming the code of the
// plugins/presets that we are require-ing themselves before setting up the
// actual config.
require('@babel/register')({only: [], babelrc: false, configFile: false});
require('@babel/register')(config(onlyList));
}
function config(onlyList) {
_only = _only.concat(onlyList);'use strict';
const escapeRegExp = require('escape-string-regexp');
const path = require('path');
require('./node-polyfills');
var _only = [];
const PLUGINS = [
[require('@babel/plugin-transform-flow-strip-types').default],
[require('@babel/plugin-proposal-object-rest-spread').default],
[require('@babel/plugin-proposal-class-properties').default],
[require('@babel/plugin-transform-modules-commonjs').default],
[require('@babel/plugin-proposal-nullish-coalescing-operator').default],
[require('@babel/plugin-proposal-optional-catch-binding').default],
[require('@babel/plugin-proposal-optional-chaining').default],
];
if (/^v[0-7]\./.test(process.version)) {
PLUGINS.push([require('@babel/plugin-transform-async-to-generator').default]);
}
function registerOnly(onlyList) {
// This prevents `babel-register` from transforming the code of the
// plugins/presets that we are require-ing themselves before setting up the
// actual config.
require('@babel/register')({only: [], babelrc: false});
require('@babel/register')(config(onlyList));
}
function config(onlyList) {
_only = _only.concat(onlyList);try {
// eslint-disable-next-line import/no-extraneous-dependencies
const version = require('@babel/helpers/package.json').version
babelHelperVersion.version = version
} catch (e) {
// if something goes wrong, continue and don't try to explicitly set a helper version
}
plugins = plugins.concat([
require('babel-plugin-macros'),
require('@babel/plugin-transform-destructuring').default,
[require('@babel/plugin-proposal-decorators').default, { legacy: true }], // must run before themeable-styles plugin below
[require('@babel/plugin-proposal-class-properties').default, { loose: true }],
require('@babel/plugin-proposal-export-default-from').default,
[require('@babel/plugin-proposal-object-rest-spread').default, { useBuiltIns: true }],
require('@babel/plugin-proposal-optional-chaining').default,
[require('@babel/plugin-transform-runtime').default, {
...babelHelperVersion,
corejs: false,
regenerator: true,
helpers: true,
useESModules: opts.esModules
}],
require('@babel/plugin-syntax-dynamic-import').default,
require('babel-plugin-transform-undefined-to-void')
])
if (process.env.NODE_ENV === 'production') {
plugins.push(
require('@babel/plugin-transform-react-constant-elements').default
)
}es2018 && edge
? require('@babel/plugin-proposal-async-generator-functions')
: require('@babel/plugin-syntax-async-generators'),
es2019 &&
(edge
? require('@babel/plugin-proposal-optional-catch-binding')
: require('@babel/plugin-syntax-optional-catch-binding')),
/* shippedProposals */
shippedProposals &&
(edge
? require('@babel/plugin-proposal-json-strings')
: require('@babel/plugin-syntax-json-strings')),
shippedProposals &&
require('@babel/plugin-proposal-optional-chaining').default,
shippedProposals &&
require('@babel/plugin-proposal-nullish-coalescing-operator').default,
].filter(Boolean),
};
};// the correct version is used
// https://github.com/babel/babel/blob/090c364a90fe73d36a30707fc612ce037bdbbb24/packages/babel-plugin-transform-runtime/src/index.js#L35-L42
absoluteRuntime: absoluteRuntimePath,
},
],
isEnvProduction && [
// Remove PropTypes from production build
require('babel-plugin-transform-react-remove-prop-types').default,
{
removeImport: true,
},
],
// Adds syntax support for import()
require('@babel/plugin-syntax-dynamic-import').default,
// Adds syntax support for optional chaining (?.)
require('@babel/plugin-proposal-optional-chaining').default,
// Adds syntax support for default value using ?? operator
require('@babel/plugin-proposal-nullish-coalescing-operator').default,
isEnvTest &&
// Transform dynamic import to require
require('babel-plugin-dynamic-import-node'),
].filter(Boolean),
overrides: [
isFlowEnabled && {
exclude: /\.tsx?$/,
plugins: [require('@babel/plugin-transform-flow-strip-types').default],
},
isTypeScriptEnabled && {
test: /\.tsx?$/,
plugins: [
[
require('@babel/plugin-proposal-decorators').default,function testOnlyBabel(babel: any, babelOptions: any, nodeVersion: string) {
// out test dir can be located outside of electron-builder node_modules and babel cannot resolve string names of preset
babelOptions.presets = [
[require("@babel/preset-env").default, {targets: {node: nodeVersion}}],
require("@babel/preset-react"),
]
babelOptions.plugins = [
// stage 0
require("@babel/plugin-proposal-function-bind").default,
// stage 1
require("@babel/plugin-proposal-export-default-from").default,
require("@babel/plugin-proposal-logical-assignment-operators").default,
[require("@babel/plugin-proposal-optional-chaining").default, {loose: false}],
[require("@babel/plugin-proposal-pipeline-operator").default, {proposal: "minimal"}],
[require("@babel/plugin-proposal-nullish-coalescing-operator").default, {loose: false}],
require("@babel/plugin-proposal-do-expressions").default,
// stage 2
[require("@babel/plugin-proposal-decorators").default, {legacy: true}],
require("@babel/plugin-proposal-function-sent").default,
require("@babel/plugin-proposal-export-namespace-from").default,
require("@babel/plugin-proposal-numeric-separator").default,
require("@babel/plugin-proposal-throw-expressions").default,
// stage 3
require("@babel/plugin-syntax-dynamic-import").default,
require("@babel/plugin-syntax-import-meta").default,
[require("@babel/plugin-proposal-class-properties").default, {loose: false}],
require("@babel/plugin-proposal-json-strings").default,function plugins(api, opts = {}) {
return cleanList([
require('@babel/plugin-syntax-dynamic-import').default,
require('@babel/plugin-syntax-export-default-from').default,
require('@babel/plugin-syntax-export-namespace-from').default,
require('@babel/plugin-proposal-optional-chaining').default,
require('@babel/plugin-proposal-nullish-coalescing-operator').default,
[require('@babel/plugin-proposal-decorators').default, {legacy: true}],
[require('@babel/plugin-proposal-class-properties').default, {loose: true}],
[
require('babel-plugin-transform-react-remove-prop-types').default,
{
wrap: true
}
],
[
require('@babel/plugin-proposal-object-rest-spread').default,
{useBuiltIns: true} // asume Object.assign is available by browser or polyfill
],
[
require('@babel/plugin-transform-runtime').default,
{* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
const envPreset = require('@babel/preset-env');
const reactPreset = require('@babel/preset-react');
const syntaxDynamicImport = require('@babel/plugin-syntax-dynamic-import').default;
const proposalClassProperties = require('@babel/plugin-proposal-class-properties').default;
const exportDefaultFrom = require('@babel/plugin-proposal-export-default-from').default;
const proposalOptionalChaining = require('@babel/plugin-proposal-optional-chaining').default;
const { browserlist, legacyBrowserList } = require('./browserlist');
module.exports = () => ({
env: {
modern: {
presets: [
[envPreset, {
targets: {
browsers: browserlist,
node: '10.13.0',
},
}],
],
},
},@babel/plugin-proposal-optional-chaining
Transform optional chaining operators into a series of nil checks
