jsonpointer.js

function Pointer(value) {
    if (!(this instanceof Pointer)) return new Pointer(value);
    value = value.toString().split("/");
    // remove a path component if all are empty
    var empty = !value.some(function(i) { return i });
    if (empty) value.pop();
    this.path = value.map(function(part) {
        return decodeURIComponent(part);
    });
}

Pointer.prototype.toString = function() {
    // copy resolution array
    value = this.path.map(function(i) { return i});
    if (!value.length) return "";
    // add an empty path component if all are empty
    var empty = !value.some(function(i) { return i });
    if (empty) value.push("");
    return value.map(function(part) {
        return encodeURIComponent(part);
    }).join("/");
};

Pointer.prototype.toSource = function() {
    return '[' + this.path.map(function(i) {
        return '"' + i + '"';
    }).join('][') + ']';
};

Pointer.prototype.valueOf = function() {
    return this.path;
};

module.exports = Pointer;

if (require.main === module) {
    var assert = require("assert");
    var pairs = [
        ["", []],
        ["/", [""]],
        ["/a", ["","a"]],
        ["/a/", ["","a",""]],
        ["//a", ["","","a"]],
        ["//a/", ["","","a",""]],
        ["//a//", ["","","a","",""]],
        ["/a//", ["","a","",""]],
        ["/a/", ["","a",""]],
        ["//", ["",""]],
        ["///", ["","",""]],
        ["a", ["a"]],
        ["a/", ["a",""]],
        ["a/b", ["a","b"]],
        ["a/b/", ["a","b",""]],
        ["a//", ["a","",""]]
    ];
    pairs.forEach(function(pair) {
        var pointer = Pointer(pair[0]);
        assert.equal(pair[0], "" + pointer);
        assert.deepEqual(pair[1], pointer.path);
    });

}