The kotlinx.io.core.String(ByteArray, Int, Int, Charset) function ignores the length and offset arguments on JS

[mrapplexz]

Description

Looks like the kotlinx.io.core.String(ByteArray, Int, Int, Charset) function just ignores the length and offset arguments on JS. For example, the String(byteArrayOf(64, 64, 67, 67), length = 2, offset = 1) expression will return @@CC instead of @C.

Steps to Reproduce:

1. Create a new Kotlin/JavaScript + Gradle project using IntelliJ IDEA.
2. Make the build.gradle file look like that:

plugins {
    id 'java'
    id 'kotlin2js' version '1.3.20-dev-592'
}

group 'com.company.test'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    jcenter()
    maven { url 'http://dl.bintray.com/kotlin/kotlin-dev' }
    maven { url 'http://dl.bintray.com/kotlin/kotlinx' }
}

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib-js"
    compile "org.jetbrains.kotlin:kotlin-test-js"
    compile "org.jetbrains.kotlinx:kotlinx-io-js:0.1.0-alpha-17-rc13"
}

compileKotlin2Js {
    kotlinOptions.moduleKind = 'umd'
}

3. Make the settings.gradle file look like that:

pluginManagement {
    resolutionStrategy {
        eachPlugin {
            if (requested.id.id == "kotlin2js") {
                useModule("org.jetbrains.kotlin:kotlin-gradle-plugin:${requested.version}")
            }
        }
    }

    repositories {
        jcenter()
        maven { url 'http://dl.bintray.com/kotlin/kotlin-dev' }
    }
}
rootProject.name = 'test'

4. Create a new package named "com.company.test" and a "Test.kt" file inside it with the following contents:

package com.company.test

import kotlinx.io.core.String

fun main(args: Array<String>) {
    println(String(byteArrayOf(64, 64, 67, 67), length = 2, offset = 1))
}

5. Build the project and run it using Node.JS (I've been using v10.11.0).
6. The @@CC will be printed instead of @C :disappointed:.

[mrapplexz]

Looks like an array returned by the TypedArray#subarray(...) method uses the same buffer as the original array: The subarray() method returns a new TypedArray on the same ArrayBuffer store and with the same element types as for this TypedArray object. So, i8.subarray(offset, offset + length).buffer will return the original ArrayBuffer and will ignore the offset and length parameters :/.

[fzhinkin]

We're rebooting the kotlinx-io development (see https://github.com/Kotlin/kotlinx-io/issues/131), all issues related to the previous versions will be closed. Consider reopening it if the issue remains (or the feature is still missing) in a new version.