Codemod to convert x.viewModel() to canViewModel(x) and add var canViewModel = require('can-view-model');

can-view-model-codemod.js

export default function(file, api) {
    const j = api.jscodeshift;
    const root = j(file.source);

    const removeViewModel = p => {
      
        if (p.node.expression.type === 'CallExpression' && p.node.expression.callee.property && p.node.expression.callee.property.name === 'viewModel') {
            p.node.expression = p.node.expression.callee.object;
            var ast = j.callExpression(j.identifier('canViewModel'), [p.node.expression]);
          	p.node.expression = ast;
            addNodeToBody(node)
          
        }
    };
  
      const addNodeToBody = node => root.find(j.Program).get('body').value.unshift(node);
      const constructNode = () => {
        const requireStatement = j.callExpression(j.identifier('require'), [j.literal('can-view-model')])
        const variableName = j.variableDeclarator(j.identifier('canViewModel'), requireStatement);
        return j.variableDeclaration('var', [variableName])
      }
    const node = constructNode();
  
    return root
        .find(j.ExpressionStatement)
        .forEach(removeViewModel)
        .toSource();
}