@ndn/naming-convention2

@ndn/naming-convention2

This package is part of NDNts, Named Data Networking libraries for the modern web.

This package implements NDN naming conventions based on typed components.

The current format, sometimes known as rev3 format, is specified in NDN-TR-0022 revision 3 and Name Component Type Assignment rev28, published in 2021. It is supported in most other libraries and recommended for new applications.

import { Keyword, Version, Segment, AltUri } from "@ndn/naming-convention2";
// We also have ByteOffset, Timestamp, SequenceNum.

// other imports for examples
import { Name } from "@ndn/packet";
import { strict as assert } from "node:assert";

// convention.create() returns a Component.
let name = new Name(["A", Keyword.create("metadata")]);
assert.equal(name.toString(), "/8=A/32=metadata");

// name.append() has an overload for convention component.
name = name.append(Version, 3);
assert.equal(name.toString(), "/8=A/32=metadata/54=%03");
name = name.append(Segment, 0);
assert.equal(name.toString(), "/8=A/32=metadata/54=%03/50=%00");

// convention.match() checks whether a Component follows the convention.
assert.equal(Segment.match(name.at(-1)), true);
assert.equal(Version.match(name.at(-1)), false);

// Or you can use component.is().
assert.equal(name.at(-1).is(Segment), true);
assert.equal(name.at(-1).is(Version), false);

// convention.parse() extracts the value from a Component.
assert.equal(Keyword.parse(name.at(-3)), "metadata");
assert.equal(Version.parse(name.at(-2)), 3);
assert.equal(Segment.parse(name.at(-1)), 0);

// Or you can use component.as().
assert.equal(name.at(-3).as(Keyword), "metadata");
assert.equal(name.at(-2).as(Version), 3);
assert.equal(name.at(-1).as(Segment), 0);

// If you need alternate URI syntax, use AltUri.ofName() or AltUri.ofComponent().
// Make sure you are importing AltUri from this package, not from @ndn/packet package.
assert.equal(AltUri.ofName(name), "/A/32=metadata/v=3/seg=0");
assert.equal(AltUri.ofComponent(name.at(2)), "v=3");
// This feature is not in the regular component.toString() and name.toString() methods,
// because not every application would adopt this particular set of naming conventions.
// It is incorrect to interpret "54=%03" as "version 3" everywhere, because in some applications
// it could mean something completely different.
// Using AltUri from this package indicates you have adopted these naming conventions.

// Use AltUri.parseName() and AltUri.parseComponent() to parse from alternate URI syntax.
assert(AltUri.parseName("/A/32=metadata/v=3/seg=0").equals(name));
assert(AltUri.parseComponent("v=3").equals(name.at(2)));

This package also implements rev2 format, as specified in NDN-TR-0022 revision 2 and Name Component Type Assignment rev17, published in 2019. Import Segment2, ByteOffset2, Version2, Timestamp2, SequenceNum2, AltUri2 to access this format. You should not use this outdated and obsolete format in new applications, except for accessing old data.