#Implementing Milestones

Milestones are objects that dictate how ARK Core behaves after certain heights are reached. Lets have a look at the mainnet milestones to understand this better.

 1[
 2    {
 3        "height": 1,
 4        "reward": 0,
 5        "activeDelegates": 51,
 6        "blocktime": 8,
 7        "block": {
 8            "version": 0,
 9            "maxTransactions": 50,
10            "maxPayload": 2097152,
11            "acceptExpiredTransactionTimestamps": true
12        },
13        "epoch": "2017-03-21T13:00:00.000Z",
14        "fees": {
15            "staticFees": {
16                "transfer": 10000000,
17                "secondSignature": 500000000,
18                "delegateRegistration": 2500000000,
19                "vote": 100000000,
20                "multiSignature": 500000000,
21                "ipfs": 500000000,
22                "multiPayment": 10000000,
23                "delegateResignation": 2500000000,
24                "htlcLock": 10000000,
25                "htlcClaim": 0,
26                "htlcRefund": 0
27            }
28        },
29        "vendorFieldLength": 64
30    },
31    {
32        "height": 75600,
33        "reward": 200000000
34    },
35    {
36        "height": 6600000,
37        "block": {
38            "maxTransactions": 150,
39            "maxPayload": 6300000
40        }
41    },
42    {
43        "height": 8128000,
44        "vendorFieldLength": 255
45    },
46    {
47        "height": 8204000,
48        "block": {
49            "idFullSha256": true
50        }
51    }
52]

The first milestone starts at height 1, which is the genesis block which gets generated when you create a new network configuration.

 1{
 2    "height": 1,
 3    "reward": 0, // Each forged block yields 0 rewards for the forger
 4    "activeDelegates": 51, // 51 delegates can forge at any given time
 5    "blocktime": 8, // Time in which a block is expected to be forged
 6    "block": {
 7        "version": 0,
 8        "maxTransactions": 50, // Maximum of transactions allowed to be forged per block
 9        "maxPayload": 2097152, // Maximum size of a block in bytes
10        "acceptExpiredTransactionTimestamps": true
11    },
12    "epoch": "2017-03-21T13:00:00.000Z", // Start time of the network
13    "fees": {
14        "staticFees": {
15            "transfer": 10000000, // Fee for type 0
16            "secondSignature": 500000000, // Fee for type 1
17            "delegateRegistration": 2500000000, // Fee for type 2
18            "vote": 100000000, // Fee for type 3
19            "multiSignature": 500000000, // Fee for type 4
20            "ipfs": 500000000, // Fee for type 5
21            "multiPayment": 10000000, // Fee for type 6
22            "delegateResignation": 2500000000, // Fee for type 7
23            "htlcLock": 10000000, // Fee for type 8
24            "htlcClaim": 0, // Fee for type 9
25            "htlcRefund": 0 // Fee for type 10
26        }
27    },
28    "vendorFieldLength": 64 // Maximum length of the vendor field for type 0 transactions
29}

This first milestone serves as the base for all future milestones. Lets take a look at what below milestones do.

 1[
 2    {
 3        // From height 75600 onwards we will reward 2 ARK for every forged block
 4        "height": 75600,
 5        "reward": 200000000
 6    },
 7    {
 8        // From height 6600000 onwards we will allow 150 transactions
 9        // to be forged per block with a maximum size of 6300000 bytes
10        "height": 6600000,
11        "block": {
12            "maxTransactions": 150,
13            "maxPayload": 6300000
14        }
15    },
16    {
17        // From height 8128000 onwards we will allow the vendor field
18        // for type 0 transactions to be 255 characters long
19        "height": 8128000,
20        "vendorFieldLength": 255
21    },
22    {
23        // From height 8204000 onwards we will require that
24        // all block IDs are SHA256 strings instead of numerical IDs
25        "height": 8204000,
26        "block": {
27            "idFullSha256": true
28        }
29    }
30]

Each future milestone will be merged with its predecessors to ensure all values necessary are present.

#Working With Milestones

Sometimes you might have the need to get a milestone for a specific height or need all of them to perform some statistical calculations. The @arkecosystem/crypto package makes this easy through its configuration manager that manages the state of the configuration and related milestones.

#Getting All Milestones

1import { Managers } from "@arkecosystem/config";
2 
3const milestones: object[] = Managers.configManagers.getMilestones();

#Getting The Milestone For A Given Height

1import { Managers } from "@arkecosystem/config";
2 
3const milestone: object = Managers.configManagers.getMilestone(75600);

#Determining If A Given Height Is A Milestone

1import { Managers } from "@arkecosystem/config";
2 
3const isNewMilestone: boolean = Managers.configManagers.isNewMilestone(75600);