Type.getProperties() throws TypeError

Describe the bug Version: 14.1.0

Type.getProperties() throws the following error:

/Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/compiler/common/Symbol.js:94
        return this.compilerSymbol.declarations.map(function (d) { return _this.context.compilerFactory.getNodeFromCompilerNode(d, _this.context.compilerFactory.getSourceFileForNode(d)); });
                                                ^
TypeError: Cannot read property 'map' of undefined
    at Symbol.getDeclarations (/Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/compiler/common/Symbol.js:94:49)
    at new Symbol (/Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/compiler/common/Symbol.js:18:14)
    at /Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/factories/CompilerFactory.js:388:74
    at WeakCache.getOrCreate (/Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/utils/collections/WeakCache.js:14:20)
    at CompilerFactory.getSymbol (/Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/factories/CompilerFactory.js:388:33)
    at /Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/compiler/type/Type.js:130:106
    at Array.map (<anonymous>)
    at Type.getProperties (/Users/rhys/Projects/ts-simple-ast-test/node_modules/ts-simple-ast/dist/compiler/type/Type.js:130:50)
    at Object.<anonymous> (/Users/rhys/Projects/ts-simple-ast-test/pick.ts:53:6)
    at Module._compile (module.js:641:30)

To Reproduce

I’ve created a repo that can reproduce the error with full code to reproduce issue.

Run yarn install && yarn run pick.

Strangely it only fails if I set the config file which I copied from my other project.

Essence of the issue:

const sourceFile = project.createSourceFile(
    "src/index.ts", `
    interface Foo {
        a: number,
        b: number,
    }
    export type Picked = Pick<Foo, "a">
`);

const type = sourceFile.getTypeAliases()[0].getType();

type.getProperties() // <-- THIS LINE THROWS

Expected behavior

Return an array of properties.

[rhys-vdw]

I believe you’re on the right track…

Oh, yeah. Awesome. It does do what I want. Misinterpreted the change. Think I’m close to finishing my lib now.

[dsherret]

Yeah it was because that property (this.compilerSymbol.declarations) was nullable when the compiler api’s definitions say it won’t be. I’m too lazy to create a simple reproducible example and report it to them at the moment though (it will probably be fixed sometime in the future anyway because they’ve been doing some analysis on where they do suspicious non-null assertions).

What do you mean by handling the properties of that? For that, I believe you’re on the right track and type.getProperties() should return that single a property as is happening in this test.