jscodeshift codemod to add "use strict" to any file where it is not already the first statement

addUseStrict.js

module.exports = function (fileInfo, {
    jscodeshift,
}, options) {
    // Work around for https://github.com/facebook/jscodeshift/issues/262
    const isUnix = fileInfo.source.indexOf('\r\n') === -1;
    const dom = jscodeshift(fileInfo.source);
    const topLevelStatements = jscodeshift(dom.get('program', 'body').value).filter(path => {
        return jscodeshift.Statement.check(path.node);
    });
    // Don’t add another one if it is already there.
    if (topLevelStatements.length > 0 && isUseStrictStatement(topLevelStatements.get(0).node)) {
        return;
    }
    dom.get('program', 'body').unshift(jscodeshift.expressionStatement(jscodeshift.literal('use strict')));
    return dom.toSource().replace(/\r\n/g, isUnix ? '\n' : '\r\n');

    function isUseStrictStatement(node) {
        return jscodeshift.ExpressionStatement.check(node)
            && jscodeshift.Literal.check(node.expression)
            && node.expression.value === 'use strict';
    }
};