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- "use strict";
-
- Object.defineProperty(exports, "__esModule", {
- value: true
- });
- exports.evaluateTruthy = evaluateTruthy;
- exports.evaluate = evaluate;
- const VALID_CALLEES = ["String", "Number", "Math"];
- const INVALID_METHODS = ["random"];
-
- function evaluateTruthy() {
- const res = this.evaluate();
- if (res.confident) return !!res.value;
- }
-
- function deopt(path, state) {
- if (!state.confident) return;
- state.deoptPath = path;
- state.confident = false;
- }
-
- function evaluateCached(path, state) {
- const {
- node
- } = path;
- const {
- seen
- } = state;
-
- if (seen.has(node)) {
- const existing = seen.get(node);
-
- if (existing.resolved) {
- return existing.value;
- } else {
- deopt(path, state);
- return;
- }
- } else {
- const item = {
- resolved: false
- };
- seen.set(node, item);
-
- const val = _evaluate(path, state);
-
- if (state.confident) {
- item.resolved = true;
- item.value = val;
- }
-
- return val;
- }
- }
-
- function _evaluate(path, state) {
- if (!state.confident) return;
- const {
- node
- } = path;
-
- if (path.isSequenceExpression()) {
- const exprs = path.get("expressions");
- return evaluateCached(exprs[exprs.length - 1], state);
- }
-
- if (path.isStringLiteral() || path.isNumericLiteral() || path.isBooleanLiteral()) {
- return node.value;
- }
-
- if (path.isNullLiteral()) {
- return null;
- }
-
- if (path.isTemplateLiteral()) {
- return evaluateQuasis(path, node.quasis, state);
- }
-
- if (path.isTaggedTemplateExpression() && path.get("tag").isMemberExpression()) {
- const object = path.get("tag.object");
- const {
- node: {
- name
- }
- } = object;
- const property = path.get("tag.property");
-
- if (object.isIdentifier() && name === "String" && !path.scope.getBinding(name, true) && property.isIdentifier && property.node.name === "raw") {
- return evaluateQuasis(path, node.quasi.quasis, state, true);
- }
- }
-
- if (path.isConditionalExpression()) {
- const testResult = evaluateCached(path.get("test"), state);
- if (!state.confident) return;
-
- if (testResult) {
- return evaluateCached(path.get("consequent"), state);
- } else {
- return evaluateCached(path.get("alternate"), state);
- }
- }
-
- if (path.isExpressionWrapper()) {
- return evaluateCached(path.get("expression"), state);
- }
-
- if (path.isMemberExpression() && !path.parentPath.isCallExpression({
- callee: node
- })) {
- const property = path.get("property");
- const object = path.get("object");
-
- if (object.isLiteral() && property.isIdentifier()) {
- const value = object.node.value;
- const type = typeof value;
-
- if (type === "number" || type === "string") {
- return value[property.node.name];
- }
- }
- }
-
- if (path.isReferencedIdentifier()) {
- const binding = path.scope.getBinding(node.name);
-
- if (binding && binding.constantViolations.length > 0) {
- return deopt(binding.path, state);
- }
-
- if (binding && path.node.start < binding.path.node.end) {
- return deopt(binding.path, state);
- }
-
- if (binding && binding.hasValue) {
- return binding.value;
- } else {
- if (node.name === "undefined") {
- return binding ? deopt(binding.path, state) : undefined;
- } else if (node.name === "Infinity") {
- return binding ? deopt(binding.path, state) : Infinity;
- } else if (node.name === "NaN") {
- return binding ? deopt(binding.path, state) : NaN;
- }
-
- const resolved = path.resolve();
-
- if (resolved === path) {
- return deopt(path, state);
- } else {
- return evaluateCached(resolved, state);
- }
- }
- }
-
- if (path.isUnaryExpression({
- prefix: true
- })) {
- if (node.operator === "void") {
- return undefined;
- }
-
- const argument = path.get("argument");
-
- if (node.operator === "typeof" && (argument.isFunction() || argument.isClass())) {
- return "function";
- }
-
- const arg = evaluateCached(argument, state);
- if (!state.confident) return;
-
- switch (node.operator) {
- case "!":
- return !arg;
-
- case "+":
- return +arg;
-
- case "-":
- return -arg;
-
- case "~":
- return ~arg;
-
- case "typeof":
- return typeof arg;
- }
- }
-
- if (path.isArrayExpression()) {
- const arr = [];
- const elems = path.get("elements");
-
- for (const elem of elems) {
- const elemValue = elem.evaluate();
-
- if (elemValue.confident) {
- arr.push(elemValue.value);
- } else {
- return deopt(elem, state);
- }
- }
-
- return arr;
- }
-
- if (path.isObjectExpression()) {
- const obj = {};
- const props = path.get("properties");
-
- for (const prop of props) {
- if (prop.isObjectMethod() || prop.isSpreadElement()) {
- return deopt(prop, state);
- }
-
- const keyPath = prop.get("key");
- let key = keyPath;
-
- if (prop.node.computed) {
- key = key.evaluate();
-
- if (!key.confident) {
- return deopt(keyPath, state);
- }
-
- key = key.value;
- } else if (key.isIdentifier()) {
- key = key.node.name;
- } else {
- key = key.node.value;
- }
-
- const valuePath = prop.get("value");
- let value = valuePath.evaluate();
-
- if (!value.confident) {
- return deopt(valuePath, state);
- }
-
- value = value.value;
- obj[key] = value;
- }
-
- return obj;
- }
-
- if (path.isLogicalExpression()) {
- const wasConfident = state.confident;
- const left = evaluateCached(path.get("left"), state);
- const leftConfident = state.confident;
- state.confident = wasConfident;
- const right = evaluateCached(path.get("right"), state);
- const rightConfident = state.confident;
-
- switch (node.operator) {
- case "||":
- state.confident = leftConfident && (!!left || rightConfident);
- if (!state.confident) return;
- return left || right;
-
- case "&&":
- state.confident = leftConfident && (!left || rightConfident);
- if (!state.confident) return;
- return left && right;
- }
- }
-
- if (path.isBinaryExpression()) {
- const left = evaluateCached(path.get("left"), state);
- if (!state.confident) return;
- const right = evaluateCached(path.get("right"), state);
- if (!state.confident) return;
-
- switch (node.operator) {
- case "-":
- return left - right;
-
- case "+":
- return left + right;
-
- case "/":
- return left / right;
-
- case "*":
- return left * right;
-
- case "%":
- return left % right;
-
- case "**":
- return Math.pow(left, right);
-
- case "<":
- return left < right;
-
- case ">":
- return left > right;
-
- case "<=":
- return left <= right;
-
- case ">=":
- return left >= right;
-
- case "==":
- return left == right;
-
- case "!=":
- return left != right;
-
- case "===":
- return left === right;
-
- case "!==":
- return left !== right;
-
- case "|":
- return left | right;
-
- case "&":
- return left & right;
-
- case "^":
- return left ^ right;
-
- case "<<":
- return left << right;
-
- case ">>":
- return left >> right;
-
- case ">>>":
- return left >>> right;
- }
- }
-
- if (path.isCallExpression()) {
- const callee = path.get("callee");
- let context;
- let func;
-
- if (callee.isIdentifier() && !path.scope.getBinding(callee.node.name, true) && VALID_CALLEES.indexOf(callee.node.name) >= 0) {
- func = global[node.callee.name];
- }
-
- if (callee.isMemberExpression()) {
- const object = callee.get("object");
- const property = callee.get("property");
-
- if (object.isIdentifier() && property.isIdentifier() && VALID_CALLEES.indexOf(object.node.name) >= 0 && INVALID_METHODS.indexOf(property.node.name) < 0) {
- context = global[object.node.name];
- func = context[property.node.name];
- }
-
- if (object.isLiteral() && property.isIdentifier()) {
- const type = typeof object.node.value;
-
- if (type === "string" || type === "number") {
- context = object.node.value;
- func = context[property.node.name];
- }
- }
- }
-
- if (func) {
- const args = path.get("arguments").map(arg => evaluateCached(arg, state));
- if (!state.confident) return;
- return func.apply(context, args);
- }
- }
-
- deopt(path, state);
- }
-
- function evaluateQuasis(path, quasis, state, raw = false) {
- let str = "";
- let i = 0;
- const exprs = path.get("expressions");
-
- for (const elem of quasis) {
- if (!state.confident) break;
- str += raw ? elem.value.raw : elem.value.cooked;
- const expr = exprs[i++];
- if (expr) str += String(evaluateCached(expr, state));
- }
-
- if (!state.confident) return;
- return str;
- }
-
- function evaluate() {
- const state = {
- confident: true,
- deoptPath: null,
- seen: new Map()
- };
- let value = evaluateCached(this, state);
- if (!state.confident) value = undefined;
- return {
- confident: state.confident,
- deopt: state.deoptPath,
- value: value
- };
- }
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