Installation

ox-inventory Installation

data/weapons.lua

Add the following code snippet to the weapons file:

['WEAPON_TEARGAS'] = {
    label = 'Tear Gas',
    weight = 600,
    throwable = true,
},
-- Lines below
['WEAPON_FLASHBANG'] = {
    label = 'Flashbang',
    weight = 600,
    throwable = true,
},

Remember to restart your server after making these changes for them to take effect.

qb-inventory installation

I can't equip my Flashbang / I can't throw it / It does not explode

Ensure that you have configured qb-inventory correctly.

Example configuration:

qb-core

Add

['weapon_flashbang'] = {
    ['name'] = 'weapon_flashbang',
    ['label'] = 'Flashbang',
    ['weight'] = 1000,
    ['type'] = 'weapon',
    ['ammotype'] = nil,
    ['image'] = 'weapon_flashbang.png',
    ['unique'] = true,
    ['useable'] = false,
    ['description'] = 'Your description for weapon_flashbang'
},

right before definition of weapon_grenade under throwables section.

    -- Throwables
    ['weapon_flashbang'] = {
        ['name'] = 'weapon_flashbang',
        ['label'] = 'Flashbang',
        ['weight'] = 1000,
        ['type'] = 'weapon',
        ['ammotype'] = nil,
        ['image'] = 'weapon_flashbang.png',
        ['unique'] = true,
        ['useable'] = false,
        ['description'] = 'Your description for weapon_flashbang'
    },
    ['weapon_grenade'] = {['name'] = 'weapon_grenade', ['label'] = 'Grenade',  ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_grenade.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A handheld throwable bomb'},
    ['weapon_bzgas'] = {['name'] = 'weapon_bzgas', ['label'] = 'BZ Gas', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_bzgas.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A cannister of gas that causes extreme pain'},
    ['weapon_molotov'] = {['name'] = 'weapon_molotov', ['label'] = 'Molotov', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_molotov.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A crude bomb made of a bottle filled with a flammable liquid and fitted with a wick for lighting'},
    ['weapon_stickybomb'] = {['name'] = 'weapon_stickybomb', ['label'] = 'C4', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_stickybomb.png', ['unique'] = true, ['useable'] = false, ['description'] = 'An explosive charge covered with an adhesive that when thrown against an object sticks until it explodes'},
    ['weapon_proxmine'] = {['name'] = 'weapon_proxmine', ['label'] = 'Proxmine Grenade', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_proximitymine.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A bomb placed on the ground that detonates when going within its proximity'},
    ['weapon_snowball'] = {['name'] = 'weapon_snowball',  ['label'] = 'Snowball', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_snowball.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A ball of packed snow, especially one made for throwing at other people for fun'},
    ['weapon_pipebomb'] = {['name'] = 'weapon_pipebomb',  ['label'] = 'Pipe Bomb', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_pipebomb.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A homemade bomb, the components of which are contained in a pipe'},
    ['weapon_ball'] = {['name'] = 'weapon_ball', ['label'] = 'Ball', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = 'AMMO_BALL', ['image'] = 'weapon_ball.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A solid or hollow spherical or egg-shaped object that is kicked, thrown, or hit in a game'},
    ['weapon_smokegrenade'] = {['name'] = 'weapon_smokegrenade', ['label'] = 'Smoke Grenade', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = nil, ['image'] = 'weapon_c4.png', ['unique'] = true, ['useable'] = false, ['description'] = 'An explosive charge that can be remotely detonated'},
    ['weapon_flare'] = {['name'] = 'weapon_flare', ['label'] = 'Flare pistol', ['weight'] = 1000, ['type'] = 'weapon', ['ammotype'] = 'AMMO_FLARE', ['image'] = 'weapon_flare.png', ['unique'] = true, ['useable'] = false, ['description'] = 'A small pyrotechnic devices used for illumination and signalling'},

Add

[`weapon_flashbang`] = {
    ['name'] = 'weapon_flashbang',
    ['label'] = 'Flashbang',
    ['weapontype'] = 'Throwable',
    ['ammotype'] = nil,
    ['damagereason'] = 'Died'
},

right before definition of weapon_grenade under throwables section.

    -- Throwables
    [`weapon_flashbang`] = {
        ['name'] = 'weapon_flashbang',
        ['label'] = 'Flashbang',
        ['weapontype'] = 'Throwable',
        ['ammotype'] = nil,
        ['damagereason'] = 'Died'
    },
    [`weapon_grenade`] = {['name'] = 'weapon_grenade', ['label'] = 'Grenade', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Bombed / Exploded / Detonated / Blew up'},
    [`weapon_bzgas`] = {['name'] = 'weapon_bzgas', ['label'] = 'BZ Gas', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Died'},
    [`weapon_molotov`] = {['name'] = 'weapon_molotov', ['label'] = 'Molotov', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Torched / Flambeed / Barbecued'},
    [`weapon_stickybomb`] = {['name'] = 'weapon_stickybomb', ['label'] = 'C4', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Bombed / Exploded / Detonated / Blew up'},
    [`weapon_proxmine`] = {['name'] = 'weapon_proxmine', ['label'] = 'Proxmine Grenade', ['weapontype'] = 'Throwable',  ['ammotype'] = nil, ['damagereason'] = 'Bombed / Exploded / Detonated / Blew up'},
    [`weapon_snowball`] = {['name'] = 'weapon_snowball', ['label'] = 'Snowball', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Died'},
    [`weapon_pipebomb`] = {['name'] = 'weapon_pipebomb', ['label'] = 'Pipe Bomb', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Bombed / Exploded / Detonated / Blew up'},
    [`weapon_ball`] = {['name'] = 'weapon_ball', ['label'] = 'Ball', ['weapontype'] = 'Throwable', ['ammotype'] = 'AMMO_BALL', ['damagereason'] = 'Died'},
    [`weapon_smokegrenade`] = {['name'] = 'weapon_smokegrenade', ['label'] = 'Smoke Grenade', ['weapontype'] = 'Throwable', ['ammotype'] = nil, ['damagereason'] = 'Died'},
    [`weapon_flare`] = {['name'] = 'weapon_flare', ['label'] = 'Flare pistol', ['weapontype'] = 'Throwable', ['ammotype'] = 'AMMO_FLARE',   ['damagereason'] = 'Died'},

qb-inventory

Add weaponName == "weapon_flashbang" or in elseif section in line 556, under inventory:client:UseWeapon event handler.

RegisterNetEvent('inventory:client:UseWeapon', function(weaponData, shootbool)
    local ped = PlayerPedId()
    local weaponName = tostring(weaponData.name)
    local weaponHash = joaat(weaponData.name)
    if currentWeapon == weaponName then
        TriggerEvent('weapons:client:DrawWeapon', nil)
        SetCurrentPedWeapon(ped, `WEAPON_UNARMED`, true)
        RemoveAllPedWeapons(ped, true)
        TriggerEvent('weapons:client:SetCurrentWeapon', nil, shootbool)
        currentWeapon = nil
    elseif weaponName == "weapon_flashbang" or weaponName == "weapon_stickybomb" or weaponName == "weapon_pipebomb" or weaponName == "weapon_smokegrenade" or weaponName == "weapon_flare" or weaponName == "weapon_proxmine" or weaponName == "weapon_ball"  or weaponName == "weapon_molotov" or weaponName == "weapon_grenade" or weaponName == "weapon_bzgas" then
        TriggerEvent('weapons:client:DrawWeapon', weaponName)
        GiveWeaponToPed(ped, weaponHash, 1, false, false)
        SetPedAmmo(ped, weaponHash, 1)
        SetCurrentPedWeapon(ped, weaponHash, true)
        TriggerEvent('weapons:client:SetCurrentWeapon', weaponData, shootbool)
        currentWeapon = weaponName
    elseif weaponName == "weapon_snowball" then
        TriggerEvent('weapons:client:DrawWeapon', weaponName)
        GiveWeaponToPed(ped, weaponHash, 10, false, false)
        SetPedAmmo(ped, weaponHash, 10)
        SetCurrentPedWeapon(ped, weaponHash, true)
        TriggerServerEvent('inventory:server:snowball', 'remove')
        TriggerEvent('weapons:client:SetCurrentWeapon', weaponData, shootbool)
        currentWeapon = weaponName
    else
        TriggerEvent('weapons:client:DrawWeapon', weaponName)
        TriggerEvent('weapons:client:SetCurrentWeapon', weaponData, shootbool)
        local ammo = tonumber(weaponData.info.ammo) or 0

        if weaponName == "weapon_petrolcan" or weaponName == "weapon_fireextinguisher" then
            ammo = 4000
        end

        GiveWeaponToPed(ped, weaponHash, ammo, false, false)
        SetPedAmmo(ped, weaponHash, ammo)
        SetCurrentPedWeapon(ped, weaponHash, true)

        if weaponData.info.attachments then
            for _, attachment in pairs(weaponData.info.attachments) do
                GiveWeaponComponentToPed(ped, weaponHash, joaat(attachment.component))
            end
        end

        currentWeapon = weaponName
    end
end)

qb-hud

Add `weapon_flashbang`, after throwables in Config.WhitelistedWeaponArmed section to make it look like this:

Config.WhitelistedWeaponArmed = { -- weapons specifically whitelisted to not show armed mode
    -- miscellaneous
    `weapon_petrolcan`,
    `weapon_hazardcan`,
    `weapon_fireextinguisher`,
    -- melee
    `weapon_dagger`,
    `weapon_bat`,
    `weapon_bottle`,
    `weapon_crowbar`,
    `weapon_flashlight`,
    `weapon_golfclub`,
    `weapon_hammer`,
    `weapon_hatchet`,
    `weapon_knuckle`,
    `weapon_knife`,
    `weapon_machete`,
    `weapon_switchblade`,
    `weapon_nightstick`,
    `weapon_wrench`,
    `weapon_battleaxe`,
    `weapon_poolcue`,
    `weapon_briefcase`,
    `weapon_briefcase_02`,
    `weapon_garbagebag`,
    `weapon_handcuffs`,
    `weapon_bread`,
    `weapon_stone_hatchet`,
    -- throwables
    `weapon_flashbang`, -- add flashbang here

    `weapon_grenade`,
    `weapon_bzgas`,
    `weapon_molotov`,
    `weapon_stickybomb`,
    `weapon_proxmine`,
    `weapon_snowball`,
    `weapon_pipebomb`,
    `weapon_ball`,
    `weapon_smokegrenade`,
    `weapon_flare`
}

qb-weapons

Check in server/main.lua callback prison:server:checkThrowable. If it looks like this:

QBCore.Functions.CreateCallback('prison:server:checkThrowable', function(source, cb, weapon)
    local Player = QBCore.Functions.GetPlayer(source)

    if not Player then return cb(false) end

    if QBCore.Shared.Weapons[weapon]["name"] == "weapon_snowball" then
        Player.Functions.RemoveItem("weapon_snowball", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_pipebomb" then
        Player.Functions.RemoveItem("weapon_pipebomb", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_molotov" then
        Player.Functions.RemoveItem("weapon_molotov", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_stickybomb" then
        Player.Functions.RemoveItem("weapon_stickybomb", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_grenade" then
        Player.Functions.RemoveItem("weapon_grenade", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_bzgas" then
        Player.Functions.RemoveItem("weapon_bzgas", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_proxmine" then
        Player.Functions.RemoveItem("weapon_proxmine", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_ball" then
        Player.Functions.RemoveItem("weapon_ball", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_smokegrenade" then
        Player.Functions.RemoveItem("weapon_smokegrenade", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_flare" then
        Player.Functions.RemoveItem("weapon_flare", 1)
    else
        return cb(false)
    end
    cb(true)
end)

You gonna add weapon_flashbang here too. To make it look more like this:

QBCore.Functions.CreateCallback('prison:server:checkThrowable', function(source, cb, weapon)
    local Player = QBCore.Functions.GetPlayer(source)

    if not Player then return cb(false) end

    if QBCore.Shared.Weapons[weapon]["name"] == "weapon_snowball" then
        Player.Functions.RemoveItem("weapon_snowball", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_pipebomb" then
        Player.Functions.RemoveItem("weapon_pipebomb", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_molotov" then
        Player.Functions.RemoveItem("weapon_molotov", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_stickybomb" then
        Player.Functions.RemoveItem("weapon_stickybomb", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_grenade" then
        Player.Functions.RemoveItem("weapon_grenade", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_bzgas" then
        Player.Functions.RemoveItem("weapon_bzgas", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_proxmine" then
        Player.Functions.RemoveItem("weapon_proxmine", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_ball" then
        Player.Functions.RemoveItem("weapon_ball", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_smokegrenade" then
        Player.Functions.RemoveItem("weapon_smokegrenade", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_flare" then
        Player.Functions.RemoveItem("weapon_flare", 1)
    elseif QBCore.Shared.Weapons[weapon]["name"] == "weapon_flashbang" then
        Player.Functions.RemoveItem("weapon_flashbang", 1)
    else
        return cb(false)
    end
    cb(true)
end)

Add "flashbang", at the end of Config.Throwables section in config.lua.

Config.Throwables = {
    "ball",
    "bzgas",
    "flare",
    "grenade",
    "molotov",
    "pipebomb",
    "proxmine",
    "smokegrenade",
    "snowball",
    "stickybomb",
    "flashbang",
}

Add ['weapon_flashbang'] = 0.15, right after throwables in Config.DurabilityMultiplier.

Config.DurabilityMultiplier = {
    -- Melee
    -- ['weapon_unarmed']                = 0.15,
    ['weapon_dagger']                = 0.15,
    ['weapon_bat']                   = 0.15,
    ['weapon_bottle']                = 0.15,
    ['weapon_crowbar']               = 0.15,
    -- ['weapon_flashlight']             = 0.15,
    ['weapon_golfclub']              = 0.15,
    ['weapon_hammer']                = 0.15,
    ['weapon_hatchet']               = 0.15,
    ['weapon_knuckle']               = 0.15,
    ['weapon_knife']                 = 0.15,
    ['weapon_machete']               = 0.15,
    ['weapon_switchblade']           = 0.15,
    -- ['weapon_nightstick']             = 0.15,
    ['weapon_wrench']                = 0.15,
    ['weapon_battleaxe']             = 0.15,
    ['weapon_poolcue']               = 0.15,
    ['weapon_briefcase']             = 0.15,
    ['weapon_briefcase_02']          = 0.15,
    ['weapon_garbagebag']            = 0.15,
    ['weapon_handcuffs']             = 0.15,
    ['weapon_bread']                 = 0.15,
    ['weapon_stone_hatchet']         = 0.15,

    -- Handguns
    ['weapon_pistol']                = 0.15,
    ['weapon_pistol_mk2']            = 0.15,
    ['weapon_combatpistol']          = 0.15,
    ['weapon_appistol']              = 0.15,
    -- ['weapon_stungun']                = 0.15,
    -- ['weapon_stungun_mp']                 = 0.15,
    ['weapon_pistol50']              = 0.15,
    ['weapon_snspistol']             = 0.15,
    ['weapon_heavypistol']           = 0.15,
    ['weapon_vintagepistol']         = 0.15,
    ['weapon_flaregun']              = 0.15,
    ['weapon_marksmanpistol']        = 0.15,
    ['weapon_revolver']              = 0.15,
    ['weapon_revolver_mk2']          = 0.15,
    ['weapon_doubleaction']          = 0.15,
    ['weapon_snspistol_mk2']         = 0.15,
    ['weapon_raypistol']             = 0.15,
    ['weapon_ceramicpistol']         = 0.15,
    ['weapon_navyrevolver']          = 0.15,
    ['weapon_gadgetpistol']          = 0.15,

    -- Submachine Guns
    ['weapon_microsmg']              = 0.15,
    ['weapon_smg']                   = 0.15,
    ['weapon_smg_mk2']               = 0.15,
    ['weapon_assaultsmg']            = 0.15,
    ['weapon_combatpdw']             = 0.15,
    ['weapon_machinepistol']         = 0.15,
    ['weapon_minismg']               = 0.15,
    ['weapon_raycarbine']            = 0.15,

    -- Shotguns
    ['weapon_pumpshotgun']          = 0.15,
    ['weapon_sawnoffshotgun']       = 0.15,
    ['weapon_assaultshotgun']       = 0.15,
    ['weapon_bullpupshotgun']       = 0.15,
    ['weapon_musket']               = 0.15,
    ['weapon_heavyshotgun']         = 0.15,
    ['weapon_dbshotgun']            = 0.15,
    ['weapon_autoshotgun']          = 0.15,
    ['weapon_pumpshotgun_mk2']      = 0.15,
    ['weapon_combatshotgun']        = 0.15,

    -- Assault Rifles
    ['weapon_assaultrifle']         = 0.15,
    ['weapon_assaultrifle_mk2']     = 0.15,
    ['weapon_carbinerifle']         = 0.15,
    ['weapon_carbinerifle_mk2']     = 0.15,
    ['weapon_advancedrifle']        = 0.15,
    ['weapon_specialcarbine']       = 0.15,
    ['weapon_bullpuprifle']         = 0.15,
    ['weapon_compactrifle']         = 0.15,
    ['weapon_specialcarbine_mk2']   = 0.15,
    ['weapon_bullpuprifle_mk2']     = 0.15,
    ['weapon_militaryrifle']        = 0.15,
    ['weapon_heavyrifle']           = 0.15,

    -- Light Machine Guns
    ['weapon_mg']                   = 0.15,
    ['weapon_combatmg']             = 0.15,
    ['weapon_gusenberg']            = 0.15,
    ['weapon_combatmg_mk2']         = 0.15,

    -- Sniper Rifles
    ['weapon_sniperrifle']          = 0.15,
    ['weapon_heavysniper']          = 0.15,
    ['weapon_marksmanrifle']        = 0.15,
    ['weapon_remotesniper']         = 0.15,
    ['weapon_heavysniper_mk2']      = 0.15,
    ['weapon_marksmanrifle_mk2']    = 0.15,

    -- Heavy Weapons
    ['weapon_rpg']                  = 0.15,
    ['weapon_grenadelauncher']      = 0.15,
    ['weapon_grenadelauncher_smoke']= 0.15,
    ['weapon_emplauncher']          = 0.15,
    ['weapon_minigun']              = 0.15,
    ['weapon_firework']             = 0.15,
    ['weapon_railgun']              = 0.15,
    ['weapon_hominglauncher']       = 0.15,
    ['weapon_compactlauncher']      = 0.15,
    ['weapon_rayminigun']           = 0.15,

    -- Throwables
    ['weapon_flashbang']            = 0.15, -- add flashbang here
    ['weapon_grenade']              = 0.15,
    ['weapon_bzgas']                = 0.15,
    ['weapon_molotov']              = 0.15,
    ['weapon_stickybomb']           = 0.15,
    ['weapon_proxmine']             = 0.15,
    ['weapon_snowball']             = 0.15,
    ['weapon_pipebomb']             = 0.15,
    ['weapon_ball']                 = 0.15,
    ['weapon_smokegrenade']         = 0.15,
    ['weapon_flare']                = 0.15,

    -- Miscellaneous
    ['weapon_petrolcan']            = 0.15,
    ['weapon_fireextinguisher']     = 0.15,
    ['weapon_hazardcan']            = 0.15,
    ['weapon_fertilizercan']        = 0.15,
}

qs-inventory installation

QS-INVENTORY IS NO LONGER SUPPORTED. WE DO NOT PROVIDE SUPPORT FOR IT ANYMORE.

I can't equip my Flashbang / I can't throw it / It does not explode

Ensure that you have configured qs-inventory correctly.

Example configuration

UseWeapon.lua

Add weaponName == "weapon_flashbang" or in elseif section in line 17, under Config.InventoryPrefix..':client:UseWeapon' event handler.

Example

elseif weaponName == "weapon_flashbang" or weaponName == "weapon_stickybomb" or weaponName == "weapon_pipebomb" or weaponName == "weapon_smokegrenade" or weaponName == "weapon_flare" or weaponName == "weapon_proxmine" or weaponName == "weapon_ball"  or weaponName == "weapon_molotov" or weaponName == "weapon_grenade" or weaponName == "weapon_bzgas" then
    TriggerEvent(Config.InventoryPrefix..':client:DrawWeapon', weaponName)
    GiveWeaponToPed(ped, weaponHash, 1, false, false)
    SetPedAmmo(ped, weaponHash, 1)
    SetCurrentPedWeapon(ped, weaponHash, true)
    TriggerEvent(Config.InventoryPrefix..':client:SetCurrentWeapon', weaponData, shootbool)
    currentWeapon = weaponName

weapons.lua

Add ['weapon_flashbang'] = 0.10, under -- Throwables section in line 146, under Config.DurabilityMultiplier section.

    -- Throwables
    ['weapon_flashbang']            = 0.10,
    ['weapon_grenade']              = 0.10,
    ['weapon_bzgas']                = 0.10,
    ['weapon_molotov']              = 0.10,
    ['weapon_stickybomb']           = 0.10,

shared/items.lua

Add

    ['weapon_flashbang'] =  {
        ['name'] =  'weapon_flashbang',
        ['label'] =  'Flashbang',
        ['weight'] =  1000,
        ['type'] =  'weapon',
        ['ammotype'] =  nil,
        ['image'] =  'weapon_flashbang.png',
        ['unique'] =  true,
        ['useable'] =  false,
        ['description'] =  'Flashbang'
    },

under -- Throwables section in line 1016, under ItemList section.

    -- Throwables
    ['weapon_flashbang'] =  {
        ['name'] =  'weapon_flashbang',
        ['label'] =  'Flashbang',
        ['weight'] =  1000,
        ['type'] =  'weapon',
        ['ammotype'] =  nil,
        ['image'] =  'weapon_flashbang.png',
        ['unique'] =  true,
        ['useable'] =  false,
        ['description'] =  'Flashbang'
    },
    ['weapon_grenade'] =  {
        ['name'] =  'weapon_grenade',
        ['label'] =  'Grenade',
        ['weight'] =  1000,
        ['type'] =  'weapon',
        ['ammotype'] =  nil,
        ['image'] =  'weapon_grenade.png',
        ['unique'] =  true,
        ['useable'] =  false,
        ['description'] =  'A handheld throwable bomb'
    },

shared/weapons.lua

Add

    [`weapon_flashbang`] =  {
        ['name'] =  'weapon_flashbang',
        ['label'] =  'Flashbang',
        ['weapontype'] =  'Throwable',
        ['ammotype'] =  nil,
        ['damagereason'] =  'Died'
    },

under -- Throwables section in line 677, under ItemList section.

    -- Throwables
    [`weapon_flashbang`] =  {
        ['name'] =  'weapon_flashbang',
        ['label'] =  'Flashbang',
        ['weapontype'] =  'Throwable',
        ['ammotype'] =  nil,
        ['damagereason'] =  'Died'
    },
    [`weapon_grenade`] =  {
        ['name'] =  'weapon_grenade',
        ['label'] =  'Grenade',
        ['weapontype'] =  'Throwable',
        ['ammotype'] =  nil,
        ['damagereason'] =  'Bombed / Exploded / Detonated / Blew up'
    },

quasar_fix.lua

Due to the fact that qs-inventory has a bug that was not fixed for a very long time, there is a need to implement a fix.

Create a file named quasar_fix.lua in main directory of qs-inventory.

Add those lines into freshly created quasar_fix.lua file.

local removeAllPedWeaponsOld = RemoveAllPedWeapons

RemoveAllPedWeapons = function(ped, p1)
    Citizen.Wait(50)
    removeAllPedWeaponsOld(ped, p1)
end

Then add line "quasar_fix.lua", in line 33 in file fxmanifest.lua under client_scripts section.