package.lib.path.inference.inferer-reference.js Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of traverse Show documentation
The Babel Traverse module maintains the overall tree state, and is responsible for replacing, removing, and adding nodes
There is a newer version: 7.25.7
Show newest version
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = _default;
var _t = require("@babel/types");
var _util = require("./util.js");
const {
  BOOLEAN_NUMBER_BINARY_OPERATORS,
  createTypeAnnotationBasedOnTypeof,
  numberTypeAnnotation,
  voidTypeAnnotation
} = _t;
function _default(node) {
  if (!this.isReferenced()) return;
  const binding = this.scope.getBinding(node.name);
  if (binding) {
    if (binding.identifier.typeAnnotation) {
      return binding.identifier.typeAnnotation;
    } else {
      return getTypeAnnotationBindingConstantViolations(binding, this, node.name);
    }
  }
  if (node.name === "undefined") {
    return voidTypeAnnotation();
  } else if (node.name === "NaN" || node.name === "Infinity") {
    return numberTypeAnnotation();
  } else if (node.name === "arguments") {}
}
function getTypeAnnotationBindingConstantViolations(binding, path, name) {
  const types = [];
  const functionConstantViolations = [];
  let constantViolations = getConstantViolationsBefore(binding, path, functionConstantViolations);
  const testType = getConditionalAnnotation(binding, path, name);
  if (testType) {
    const testConstantViolations = getConstantViolationsBefore(binding, testType.ifStatement);
    constantViolations = constantViolations.filter(path => !testConstantViolations.includes(path));
    types.push(testType.typeAnnotation);
  }
  if (constantViolations.length) {
    constantViolations.push(...functionConstantViolations);
    for (const violation of constantViolations) {
      types.push(violation.getTypeAnnotation());
    }
  }
  if (!types.length) {
    return;
  }
  return (0, _util.createUnionType)(types);
}
function getConstantViolationsBefore(binding, path, functions) {
  const violations = binding.constantViolations.slice();
  violations.unshift(binding.path);
  return violations.filter(violation => {
    violation = violation.resolve();
    const status = violation._guessExecutionStatusRelativeTo(path);
    if (functions && status === "unknown") functions.push(violation);
    return status === "before";
  });
}
function inferAnnotationFromBinaryExpression(name, path) {
  const operator = path.node.operator;
  const right = path.get("right").resolve();
  const left = path.get("left").resolve();
  let target;
  if (left.isIdentifier({
    name
  })) {
    target = right;
  } else if (right.isIdentifier({
    name
  })) {
    target = left;
  }
  if (target) {
    if (operator === "===") {
      return target.getTypeAnnotation();
    }
    if (BOOLEAN_NUMBER_BINARY_OPERATORS.includes(operator)) {
      return numberTypeAnnotation();
    }
    return;
  }
  if (operator !== "===" && operator !== "==") return;
  let typeofPath;
  let typePath;
  if (left.isUnaryExpression({
    operator: "typeof"
  })) {
    typeofPath = left;
    typePath = right;
  } else if (right.isUnaryExpression({
    operator: "typeof"
  })) {
    typeofPath = right;
    typePath = left;
  }
  if (!typeofPath) return;
  if (!typeofPath.get("argument").isIdentifier({
    name
  })) return;
  typePath = typePath.resolve();
  if (!typePath.isLiteral()) return;
  const typeValue = typePath.node.value;
  if (typeof typeValue !== "string") return;
  return createTypeAnnotationBasedOnTypeof(typeValue);
}
function getParentConditionalPath(binding, path, name) {
  let parentPath;
  while (parentPath = path.parentPath) {
    if (parentPath.isIfStatement() || parentPath.isConditionalExpression()) {
      if (path.key === "test") {
        return;
      }
      return parentPath;
    }
    if (parentPath.isFunction()) {
      if (parentPath.parentPath.scope.getBinding(name) !== binding) return;
    }
    path = parentPath;
  }
}
function getConditionalAnnotation(binding, path, name) {
  const ifStatement = getParentConditionalPath(binding, path, name);
  if (!ifStatement) return;
  const test = ifStatement.get("test");
  const paths = [test];
  const types = [];
  for (let i = 0; i < paths.length; i++) {
    const path = paths[i];
    if (path.isLogicalExpression()) {
      if (path.node.operator === "&&") {
        paths.push(path.get("left"));
        paths.push(path.get("right"));
      }
    } else if (path.isBinaryExpression()) {
      const type = inferAnnotationFromBinaryExpression(name, path);
      if (type) types.push(type);
    }
  }
  if (types.length) {
    return {
      typeAnnotation: (0, _util.createUnionType)(types),
      ifStatement
    };
  }
  return getConditionalAnnotation(binding, ifStatement, name);
}

//# sourceMappingURL=inferer-reference.js.map