string-refs.js

/**
 * Copyright 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 */

"use strict";

export default (file, api, options) => {
  const j = api.jscodeshift;

  const printOptions = options.printOptions || {
    quote: "single",
    trailingComma: true,
  };

  const root = j(file.source);

  let hasModifications = false;

  root
    .find(j.JSXAttribute, (node) => {
      return node.name.name === "ref";
    })
    .forEach((jsxAttributePath) => {
      const valuePath = jsxAttributePath.get("value");
      if (
        // Flow parser
        valuePath.value.type === "Literal" ||
        // TSX parser
        valuePath.value.type === "StringLiteral"
      ) {
        hasModifications = true;
        // This might shadow existing variables.
        // But this should be safe since we control what identifiers we're reading in this block.
        // It will trigger ESLint's `no-shadow` though.
        // Babel has a helper to get a identifier that doesn't shadow existing vars.
        // Maybe JSCodeShift has such a helper as well?
        const currentIdentifierName = "current";
        valuePath.replace(
          // {(current) => { this.refs[valuePath.node.value] = current }}
          j.jsxExpressionContainer(
            j.arrowFunctionExpression(
              [j.identifier(currentIdentifierName)],
              j.blockStatement([
                j.expressionStatement(
                  j.assignmentExpression(
                    "=",
                    j.memberExpression(
                      j.memberExpression(
                        j.thisExpression(),
                        j.identifier("refs")
                      ),
                      j.literal(valuePath.node.value)
                    ),
                    j.identifier(currentIdentifierName)
                  )
                ),
              ])
            )
          )
        );
      }
    });

  return hasModifications ? root.toSource(printOptions) : file.source;
};