blob: 8f5a832a31887f0506a15e2baa23fadff58cb4a2 [file] [log] [blame]
var assert = require('assert');
var dict = require('./dict');
var Parser = require('./parser');
var Handlers = require('./handlers');
var JSONPath = function() {
this.initialize.apply(this, arguments);
};
JSONPath.prototype.initialize = function() {
this.parser = new Parser();
this.handlers = new Handlers();
};
JSONPath.prototype.parse = function(string) {
assert.ok(_is_string(string), "we need a path");
return this.parser.parse(string);
};
JSONPath.prototype.parent = function(obj, string) {
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(string, "we need a path");
var node = this.nodes(obj, string)[0];
var key = node.path.pop(); /* jshint unused:false */
return this.value(obj, node.path);
}
JSONPath.prototype.apply = function(obj, string, fn) {
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(string, "we need a path");
assert.equal(typeof fn, "function", "fn needs to be function")
var nodes = this.nodes(obj, string).sort(function(a, b) {
// sort nodes so we apply from the bottom up
return b.path.length - a.path.length;
});
nodes.forEach(function(node) {
var key = node.path.pop();
var parent = this.value(obj, this.stringify(node.path));
var val = node.value = fn.call(obj, parent[key]);
parent[key] = val;
}, this);
return nodes;
}
JSONPath.prototype.value = function(obj, path, value) {
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(path, "we need a path");
if (arguments.length >= 3) {
var node = this.nodes(obj, path).shift();
if (!node) return this._vivify(obj, path, value);
var key = node.path.slice(-1).shift();
var parent = this.parent(obj, this.stringify(node.path));
parent[key] = value;
}
return this.query(obj, this.stringify(path), 1).shift();
}
JSONPath.prototype._vivify = function(obj, string, value) {
var self = this;
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(string, "we need a path");
var path = this.parser.parse(string)
.map(function(component) { return component.expression.value });
var setValue = function(path, value) {
var key = path.pop();
var node = self.value(obj, path);
if (!node) {
setValue(path.concat(), typeof key === 'string' ? {} : []);
node = self.value(obj, path);
}
node[key] = value;
}
setValue(path, value);
return this.query(obj, string)[0];
}
JSONPath.prototype.query = function(obj, string, count) {
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(_is_string(string), "we need a path");
var results = this.nodes(obj, string, count)
.map(function(r) { return r.value });
return results;
};
JSONPath.prototype.paths = function(obj, string, count) {
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(string, "we need a path");
var results = this.nodes(obj, string, count)
.map(function(r) { return r.path });
return results;
};
JSONPath.prototype.nodes = function(obj, string, count) {
assert.ok(obj instanceof Object, "obj needs to be an object");
assert.ok(string, "we need a path");
if (count === 0) return [];
var path = this.parser.parse(string);
var handlers = this.handlers;
var partials = [ { path: ['$'], value: obj } ];
var matches = [];
if (path.length && path[0].expression.type == 'root') path.shift();
if (!path.length) return partials;
path.forEach(function(component, index) {
if (matches.length >= count) return;
var handler = handlers.resolve(component);
var _partials = [];
partials.forEach(function(p) {
if (matches.length >= count) return;
var results = handler(component, p, count);
if (index == path.length - 1) {
// if we're through the components we're done
matches = matches.concat(results || []);
} else {
// otherwise accumulate and carry on through
_partials = _partials.concat(results || []);
}
});
partials = _partials;
});
return count ? matches.slice(0, count) : matches;
};
JSONPath.prototype.stringify = function(path) {
assert.ok(path, "we need a path");
var string = '$';
var templates = {
'descendant-member': '..{{value}}',
'child-member': '.{{value}}',
'descendant-subscript': '..[{{value}}]',
'child-subscript': '[{{value}}]'
};
path = this._normalize(path);
path.forEach(function(component) {
if (component.expression.type == 'root') return;
var key = [component.scope, component.operation].join('-');
var template = templates[key];
var value;
if (component.expression.type == 'string_literal') {
value = JSON.stringify(component.expression.value)
} else {
value = component.expression.value;
}
if (!template) throw new Error("couldn't find template " + key);
string += template.replace(/{{value}}/, value);
});
return string;
}
JSONPath.prototype._normalize = function(path) {
assert.ok(path, "we need a path");
if (typeof path == "string") {
return this.parser.parse(path);
} else if (Array.isArray(path) && typeof path[0] == "string") {
var _path = [ { expression: { type: "root", value: "$" } } ];
path.forEach(function(component, index) {
if (component == '$' && index === 0) return;
if (typeof component == "string" && component.match("^" + dict.identifier + "$")) {
_path.push({
operation: 'member',
scope: 'child',
expression: { value: component, type: 'identifier' }
});
} else {
var type = typeof component == "number" ?
'numeric_literal' : 'string_literal';
_path.push({
operation: 'subscript',
scope: 'child',
expression: { value: component, type: type }
});
}
});
return _path;
} else if (Array.isArray(path) && typeof path[0] == "object") {
return path
}
throw new Error("couldn't understand path " + path);
}
function _is_string(obj) {
return Object.prototype.toString.call(obj) == '[object String]';
}
JSONPath.Handlers = Handlers;
JSONPath.Parser = Parser;
var instance = new JSONPath;
instance.JSONPath = JSONPath;
module.exports = instance;