andreypopp/autobind-decorator

boundMethod decorator might not be usable in Angular production builds

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#82 opened on Dec 13, 2018

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help wanted

Description

I get this error when running production builds of my Angular app, which contains usages of the boundMethod decorator:

 Error encountered resolving symbol values statically. Only initialized variables and constants can be referenced because the value of this variable is needed by the template compiler (position 3:22 in the original .ts file), resolving symbol boundMethod in C:/Users/Jeff/[path to my app]/node_modules/autobind-decorator/index.d.ts

I believe it is the Angular AoT compiler which is throwing this error. Devleopment builds, which don't use AoT, don't produce these errors.

I import the decorator using import { boundMethod } from "autobind-decorator";

A workaround is to use the autobind decorator instead, though that is discouraged by this package's docs.

Contributor guide

Tech stack
typescriptjavascriptangular
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScript decoratorsAngular AoT compilationES6 classes
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
The error occurs during Angular AOT compilation when using the boundMethod decorator. Investigate the decorator implementation in the package source (likely index.d.ts or boundMethod.ts) to see how it is defined. Angular AOT requires decorators to be statically analyzable. Common workarounds include using a factory function or changing the decorator to use a static property. Also explore the lib folder or the main source to understand the structure. Check if there are any existing PRs or comments addressing this issue (none visible). Consider updating the decorator to be compatible with Angular's AOT compiler by following Angular's guidelines for decorator metadata.