main.js (Minecraft Scripting API Tutorial)

import * as server from '@minecraft/server'
import * as ui from '@minecraft/server-ui'
const world = server.world

let players = world.getAllPlayers()

function newPlayer(player) {
    let lastTick = undefined
    world.events.tick.subscribe(tick => {
        if (!lastTick || tick.currentTick - lastTick >= 100) {
            if (player.isSneaking) {
                player.runCommandAsync("say I am sneaking")
                player.dimension.createExplosion(new server.Location(player.location.x, player.location.y, player.location.z), 4)
                lastTick = tick.currentTick
            }
        }
    })
}

players.forEach(newPlayer)
world.events.playerJoin.subscribe(newPlayer)

const form = new ui.ModalFormData()
form.title("Renamer")
form.textField("Rename nametag", "New Name", "")

world.events.beforeItemUse.subscribe(result => {
    if (result.item.typeId == "minecraft:name_tag") {
        form.show(result.source).then(onFulfilled => {

        })
    }
})