lib/util/get-configured-node-version.js
function getEnginesNode(filename) {
    const info = getPackageJson(filename)
    return getSemverRange(info && info.engines && info.engines.node)
}
function getEnginesNode(filename) {
    const info = getPackageJson(filename)
    return getSemverRange(info && info.engines && info.engines.node)
}
Get the `engines.node` field of package.json.
@param {string} filename The path to the current linting file.
@returns {Range|null} The range object of the `engines.node` field.