packages/babel-traverse/src/path/inference/index.js
import type NodePath from "./index";
import * as inferers from "./inferers";
import * as t from "@babel/types";
/**
* Infer the type of the current `NodePath`.
*/
export function getTypeAnnotation(): Object {
if (this.typeAnnotation) return this.typeAnnotation;
let type = this._getTypeAnnotation() || t.anyTypeAnnotation();
if (t.isTypeAnnotation(type)) type = type.typeAnnotation;
return (this.typeAnnotation = type);
}
/**
* todo: split up this method
*/
export function _getTypeAnnotation(): ?Object {
const node = this.node;
if (!node) {
// handle initializerless variables, add in checks for loop initializers too
if (this.key === "init" && this.parentPath.isVariableDeclarator()) {
const declar = this.parentPath.parentPath;
const declarParent = declar.parentPath;
// for (let NODE in bar) {}
if (declar.key === "left" && declarParent.isForInStatement()) {
return t.stringTypeAnnotation();
}
// for (let NODE of bar) {}
if (declar.key === "left" && declarParent.isForOfStatement()) {
return t.anyTypeAnnotation();
}
return t.voidTypeAnnotation();
} else {
return;
}
}
if (node.typeAnnotation) {
return node.typeAnnotation;
}
let inferer = inferers[node.type];
if (inferer) {
return inferer.call(this, node);
}
inferer = inferers[this.parentPath.type];
if (inferer?.validParent) {
return this.parentPath.getTypeAnnotation();
}
}
export function isBaseType(baseName: string, soft?: boolean): boolean {
return _isBaseType(baseName, this.getTypeAnnotation(), soft);
}
function _isBaseType(baseName: string, type?, soft?): boolean {
if (baseName === "string") {
return t.isStringTypeAnnotation(type);
} else if (baseName === "number") {
return t.isNumberTypeAnnotation(type);
} else if (baseName === "boolean") {
return t.isBooleanTypeAnnotation(type);
} else if (baseName === "any") {
return t.isAnyTypeAnnotation(type);
} else if (baseName === "mixed") {
return t.isMixedTypeAnnotation(type);
} else if (baseName === "empty") {
return t.isEmptyTypeAnnotation(type);
} else if (baseName === "void") {
return t.isVoidTypeAnnotation(type);
} else {
if (soft) {
return false;
} else {
throw new Error(`Unknown base type ${baseName}`);
}
}
}
export function couldBeBaseType(name: string): boolean {
const type = this.getTypeAnnotation();
if (t.isAnyTypeAnnotation(type)) return true;
if (t.isUnionTypeAnnotation(type)) {
for (const type2 of (type.types: Array<Object>)) {
if (t.isAnyTypeAnnotation(type2) || _isBaseType(name, type2, true)) {
return true;
}
}
return false;
} else {
return _isBaseType(name, type, true);
}
}
export function baseTypeStrictlyMatches(right: NodePath) {
const left = this.getTypeAnnotation();
right = right.getTypeAnnotation();
if (!t.isAnyTypeAnnotation(left) && t.isFlowBaseAnnotation(left)) {
return right.type === left.type;
}
}
export function isGenericType(genericName: string): boolean {
const type = this.getTypeAnnotation();
return (
t.isGenericTypeAnnotation(type) &&
t.isIdentifier(type.id, { name: genericName })
);
}