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node_modules/regenerator-transform/src/replaceShorthandObjectMethod.js 2.32 KB
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  import * as t from "babel-types";
  import * as util from "./util";
  
  // this function converts a shorthand object generator method into a normal
  // (non-shorthand) object property which is a generator function expression. for
  // example, this:
  //
  //  var foo = {
  //    *bar(baz) { return 5; }
  //  }
  //
  // should be replaced with:
  //
  //  var foo = {
  //    bar: function*(baz) { return 5; }
  //  }
  //
  // to do this, it clones the parameter array and the body of the object generator
  // method into a new FunctionExpression.
  //
  // this method can be passed any Function AST node path, and it will return
  // either:
  //   a) the path that was passed in (iff the path did not need to be replaced) or
  //   b) the path of the new FunctionExpression that was created as a replacement
  //     (iff the path did need to be replaced)
  //
  // In either case, though, the caller can count on the fact that the return value
  // is a Function AST node path.
  //
  // If this function is called with an AST node path that is not a Function (or with an
  // argument that isn't an AST node path), it will throw an error.
  export default function replaceShorthandObjectMethod(path) {
    if (!path.node || !t.isFunction(path.node)) {
      throw new Error("replaceShorthandObjectMethod can only be called on Function AST node paths.");
    }
  
    // this function only replaces shorthand object methods (called ObjectMethod
    // in Babel-speak).
    if (!t.isObjectMethod(path.node)) {
      return path;
    }
  
    // this function only replaces generators.
    if (!path.node.generator) {
      return path;
    }
  
    const parameters = path.node.params.map(function (param) {
      return t.cloneDeep(param);
    })
  
    const functionExpression = t.functionExpression(
      null, // id
      parameters, // params
      t.cloneDeep(path.node.body), // body
      path.node.generator,
      path.node.async
    );
  
    util.replaceWithOrRemove(path,
      t.objectProperty(
        t.cloneDeep(path.node.key), // key
        functionExpression, //value
        path.node.computed, // computed
        false // shorthand
      )
    );
  
    // path now refers to the ObjectProperty AST node path, but we want to return a
    // Function AST node path for the function expression we created. we know that
    // the FunctionExpression we just created is the value of the ObjectProperty,
    // so return the "value" path off of this path.
    return path.get("value");
  }