Test Save Load Code

// Compact the grid to send to the server.
packGrid() {
	let cell;
	let terminals = this.getTerminals();
	let byteCodeIndex = 0;
	let packedArr = [];
	let bitIndex = 0;
	let size = this.layeredGrid.width * this.layeredGrid.height * (this.layeredGrid.layers - 1);

	// Reduce each cell in each layer to a single bit.
	for(let ii = 0; ii < size; ii++) {
		// Get the cell and make room for the next bit.
		cell = this.layeredGrid.grid[ii];
		/*jslint bitwise: true */
		packedArr[byteCodeIndex] <<= 1;
		/*jslint bitwise: false */

		// If set, set the LSB.
		// It's 0 by default.
		if(!!cell && cell.isSet) {
			packedArr[byteCodeIndex]++;
		}

		// Increment the bit index and check if we need to move to the next word.
		bitIndex++;
		if(bitIndex > 31) {
			bitIndex = 0;
			byteCodeIndex++;
		}
	}

	// Pad the last word with zeros to the right.
	/*jslint bitwise: true */
	packedArr[packedArr.length - 1] <<= (32 - bitIndex);
	/*jslint bitwise: false */
	
	// Add the X and Y coordinates of each terminal.
	for(let ii = terminals.length - 1; ii >= 0; ii--) {
		packedArr.unshift(terminals[ii].y);
		packedArr.unshift(terminals[ii].x);
	}
	// Add the count of outputs, inputs, and width/height info.
	packedArr.unshift(this.outputs.length);
	packedArr.unshift(this.inputs.length);
	packedArr.unshift(this.layeredGrid.width);
	packedArr.unshift(this.layeredGrid.height);
	// Version number for this format.
	packedArr.unshift(1);
	return packedArr;
}

unpackGrid(packedArr) {
	let word, bit, coords;
	let offset = 5 +                                    // version, width, height, #in, #out
					2 * (packedArr[3] + packedArr[4] + 2); // X and Y for each IN,OUT,VDD,GND

	this.layeredGrid.resize(packedArr[1], packedArr[2]);
	
	while(this.inputs.length > packedArr[3]) {
		this.controller.removeTerminal();
	}
	while(this.outputs.length > packedArr[4]) {
		this.controller.removeTerminal(true);
	}
		
	while(this.inputs.length < packedArr[3]) {
		this.controller.addTerminal();
	}
	while(this.outputs.length < packedArr[4]) {
		this.controller.addTerminal(true);
	}
	
	this.vddCell.x = packedArr[5];
	this.vddCell.y = packedArr[6];
	this.gndCell.x = packedArr[7];
	this.gndCell.y = packedArr[8];
	
	for(let ii = 0; ii < packedArr[3]; ii++) {
		this.inputs[ii].x = packedArr[2*ii +  9];
		this.inputs[ii].y = packedArr[2*ii + 10];
	}
	
	for(let ii = 0; ii < packedArr[4]; ii++) {
		this.outputs[ii].x = packedArr[2*(ii + packedArr[3]) +  9];
		this.outputs[ii].y = packedArr[2*(ii + packedArr[3]) + 10];
	}
	
	for(let ii = 0; ii < 6*(packedArr[1] * packedArr[2]); ii++) {
		word = Math.floor(ii / 32);
		bit = 31 - (ii % 32);
				coords = this.layeredGrid.convertToCoordinates(ii);
		
		/*jslint bitwise: true */
		if(!!((packedArr[offset + word] >> bit) & 1)) {
		/*jslint bitwise: false */
				this.layeredGrid.grid[ii] = {
					isSet: true,
					x: coords.x,
					y: coords.y,
					layer: coords.layer,
				};
		}
		else {
			delete this.layeredGrid.grid[ii];
		}
	}
}

// Sends a compacted version of the grid and terminal coordinates to the server.
save() {
	let packedArr = this.packGrid();
	let xhr = new XMLHttpRequest();

	// Send packedArr as JSON.
	xhr.open('POST', '/api/v1/save', true);
	xhr.setRequestHeader('Content-Type', 'application/json');
	xhr.onload = function() {
		if (this.status === 200) {
			console.log("Saved!");
		} else {
			console.log("Error saving!");
		}
	};
	xhr.send(JSON.stringify(packedArr));
}

// Loads a grid from the server.
load() {
	// Get the grid by sending a POST to /api/load_v1.
	let xhr = new XMLHttpRequest();
	xhr.open('POST', '/api/v1/load', true);
	xhr.setRequestHeader('Content-Type', 'application/json');
	xhr.onload = function() {
		// Just print the response.
		if (this.status === 200) {
			console.log("Loaded!");
		} else {
			console.log("Error loading!");
		}
		this.unpackGrid(JSON.parse(xhr.responseText));
	};
	xhr.send();
}