Stopped working starting with version `1.0.30001754`

[FredericEspiau]

Hey and thanks for the hard work,

I'm a bit puzzled here and I can't provide a reproduction unfortunately.

Our project works fine if we use version 1.0.30001753 but doesn't work starting with version 1.0.30001754.

Here is the kind of errors we get:

Here is the code that triggers the error:

export var boolean = {
    is: function (u) { return typeof u === 'boolean'; }
};

export var Schemable = {
    URI: URI,
    literal: literal,
    string: string,
    number: number,
    boolean: boolean,
    nullable: nullable,
    type: type,
    struct: struct,
    partial: partial,
    record: record,
    array: array,
    tuple: tuple,
    intersect: intersect,
    sum: sum,
    lazy: function (_, f) { return lazy(f); },
    readonly: readonly
};

This is an extract from io-ts, to be more accurate the file is io-ts/es6/Guard.js.

Please note that this file is used both when using 1.0.30001753 (functional) and when using 1.0.30001754 (non-functional).

Funny thing is that if I change the code to be

export var boolean = {
    is: function (u) { return typeof u === 'boolean'; }
};

export var Schemable = {
    URI: URI,
    literal: literal,
    string: string,
    number: number,
    boolean: {
      is: function (u) { return typeof u === 'boolean'; }
    },
    nullable: nullable,
    type: type,
    struct: struct,
    partial: partial,
    record: record,
    array: array,
    tuple: tuple,
    intersect: intersect,
    sum: sum,
    lazy: function (_, f) { return lazy(f); },
    readonly: readonly
};

Then I get another error in another package totally unrelated to io-ts: int is not defined.

This happens on multiple workstations with different browsers.

Stack:
"next": "15.4.8"
"react": "19.2.1"
"typescript": "5.9.3"

We use turbopack to build our project.

Thanks in advance !

[ai]

Very likely that the problem is with the fact that updating caniuse-lite changing polyfills.

But I could not help with non-isolated issues.