Type 'IterableIterator<[number, any]>' is not an array type or a string type. Use compiler option '--downlevelIteration' to allow iterating of iterators

Ionic Framework
1

I am using ionic 4 to build an app. Whereas my app is working fine on browser but when I build android platform it is giving me error for this line

for (let [index, p] of this.cart.entries())

The error is Type ‘IterableIterator<[number, any]>’ is not an array type or a string type. Use compiler option ‘–downlevelIteration’ to allow iterating of iterators.

My typescript version is 3.7.2
The app is working fine on browser but android platform is not getting build

2

Ionic (and Angular in general) are pretty sensitive about TypeScript versions. Any time you try manually upgrading, and encounter any problem, I would first downgrade TypeScript to the version that comes in with a brand-new Ionic project and see if the problem persists.

3

I solved it by adding “downlevelIteration”: true, in compilerOptions inside tsconfig.josn file. Note my target was es2015