fix(types): return a usable type when using the sequelize.models lookup

[schmod]

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Description of change

Currently, looking up model classes via the sequelize.models interface does not yield an object with a usable type signature (for reasons that I admittedly do not entirely understand).

Static functions such as findAll and belongsTo do not work on the values pulled off of sequelize.models, presumably because these methods use the ModelCtor "hack" to infer the correct return type.

class Model1 extends Model {}

const M1 = sequelize.models.model1;
m1.findAll({});  // <-- ERROR

/**
The 'this' context of type 'typeof Model' is not assignable to method's 'this' of type 'ModelCtor<Model<unknown, unknown>>'.
  Type 'typeof Model' is not assignable to type 'new () => Model<unknown, unknown>'.
    Cannot assign an abstract constructor type to a non-abstract constructor type.ts(2684)
/**

It appears that these methods can be called if sequelize.models is redefined to contain ModelCtors instead of typeof Model.

[codecov]

Codecov Report

Merging #11293 into master will increase coverage by 0.76%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #11293      +/-   ##
==========================================
+ Coverage   95.58%   96.34%   +0.76%     
==========================================
  Files          91       94       +3     
  Lines        8855     9057     +202     
==========================================
+ Hits         8464     8726     +262     
+ Misses        391      331      -60

Impacted Files	Coverage Δ
lib/dialects/mariadb/index.js	100% <0%> (ø)
lib/dialects/mariadb/connection-manager.js	100% <0%> (ø)
lib/dialects/mariadb/query.js	87.87% <0%> (ø)
lib/dialects/abstract/query-generator.js	97.61% <0%> (+0.17%)	⬆️
lib/sequelize.js	95.95% <0%> (+0.62%)	⬆️
lib/query-interface.js	92.17% <0%> (+1.46%)	⬆️
lib/dialects/mariadb/data-types.js	100% <0%> (+49.01%)	⬆️
lib/dialects/mariadb/query-generator.js	97.87% <0%> (+87.23%)	⬆️

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[SimonSchick]

Looks ok, but we are looking to deprecate .models eventually and I would discourage the use of .models in the future for type safety.

[schmod]

Yeah, FWIW, I wouldn't mind if we added some more guidance on how to best use Sequelize in a typesafe manner, particularly with regard to model definitions.

A bunch of the tricks that folks normally use to manage associations without introducing cyclical dependencies don't quite work in the TS world.

[papb]

@schmod What kind of tricks are you referring to? Can you show an example? (No rush, and not relevant to this PR)

[sushantdhiman]

🎉 This PR is included in version 5.13.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀