优化

‘liusuyi’

2023-10-21 ae92b6823499cfab77201b4033922fa373fb37a3

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"use strict";
 
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = simplifyAccess;
var _t = require("@babel/types");
const {
  LOGICAL_OPERATORS,
  assignmentExpression,
  binaryExpression,
  cloneNode,
  identifier,
  logicalExpression,
  numericLiteral,
  sequenceExpression,
  unaryExpression
} = _t;
const simpleAssignmentVisitor = {
  UpdateExpression: {
    exit(path) {
      const {
        scope,
        bindingNames,
        includeUpdateExpression
      } = this;
      if (!includeUpdateExpression) {
        return;
      }
      const arg = path.get("argument");
      if (!arg.isIdentifier()) return;
      const localName = arg.node.name;
      if (!bindingNames.has(localName)) return;
 
      if (scope.getBinding(localName) !== path.scope.getBinding(localName)) {
        return;
      }
      if (path.parentPath.isExpressionStatement() && !path.isCompletionRecord()) {
        const operator = path.node.operator == "++" ? "+=" : "-=";
        path.replaceWith(assignmentExpression(operator, arg.node, numericLiteral(1)));
      } else if (path.node.prefix) {
        path.replaceWith(assignmentExpression("=", identifier(localName), binaryExpression(path.node.operator[0], unaryExpression("+", arg.node), numericLiteral(1))));
      } else {
        const old = path.scope.generateUidIdentifierBasedOnNode(arg.node, "old");
        const varName = old.name;
        path.scope.push({
          id: old
        });
        const binary = binaryExpression(path.node.operator[0], identifier(varName),
        numericLiteral(1));
 
        path.replaceWith(sequenceExpression([assignmentExpression("=", identifier(varName), unaryExpression("+", arg.node)), assignmentExpression("=", cloneNode(arg.node), binary), identifier(varName)]));
      }
    }
  },
  AssignmentExpression: {
    exit(path) {
      const {
        scope,
        seen,
        bindingNames
      } = this;
      if (path.node.operator === "=") return;
      if (seen.has(path.node)) return;
      seen.add(path.node);
      const left = path.get("left");
      if (!left.isIdentifier()) return;
 
      const localName = left.node.name;
      if (!bindingNames.has(localName)) return;
 
      if (scope.getBinding(localName) !== path.scope.getBinding(localName)) {
        return;
      }
      const operator = path.node.operator.slice(0, -1);
      if (LOGICAL_OPERATORS.includes(operator)) {
        path.replaceWith(logicalExpression(
        operator, path.node.left, assignmentExpression("=", cloneNode(path.node.left), path.node.right)));
      } else {
        path.node.right = binaryExpression(
        operator, cloneNode(path.node.left), path.node.right);
        path.node.operator = "=";
      }
    }
  }
};
function simplifyAccess(path, bindingNames,
includeUpdateExpression = true) {
  path.traverse(simpleAssignmentVisitor, {
    scope: path.scope,
    bindingNames,
    seen: new WeakSet(),
    includeUpdateExpression
  });
}
 
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