100 lines
3.3 KiB
JavaScript
100 lines
3.3 KiB
JavaScript
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Elm.init = function(module, baseNode) {
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'use strict';
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// defining state needed for an instance of the Elm RTS
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var signalGraph = null;
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var inputs = [];
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var visualModel = null;
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function notify(id, v) {
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var timestep = Date.now();
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var hasListener = false;
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for (var i = inputs.length; i--; ) {
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// must maintain the order of this stmt to avoid having the ||
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// short-circuiting the necessary work of recv
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hasListener = inputs[i].recv(timestep, id, v) || hasListener;
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}
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return hasListener;
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}
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// ensure that baseNode exists and is properly formatted.
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if (typeof baseNode === 'undefined') {
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baseNode = document.body;
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var style = document.createElement('style');
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style.type = 'text/css';
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style.innerHTML = "html,head,body { padding:0; margin:0; }" +
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"body { font-family: calibri, helvetica, arial, sans-serif; }";
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document.head.appendChild(style);
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}
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// create the actuall RTS. Any impure modules will attach themselves to this
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// object. This permits many Elm programs to be embedded per document.
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var elm = {notify: notify, node: baseNode, id: ElmRuntime.guid(), inputs: inputs};
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// Set up methods to communicate with Elm program from JS.
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function send(name, value) {
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if (typeof value === 'undefined') return function(v) { return send(name,v) };
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var e = document.createEvent('Event');
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e.initEvent(name + '_' + elm.id, true, true);
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e.value = value;
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document.dispatchEvent(e);
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}
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function recv(name, handler) {
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document.addEventListener(name + '_' + elm.id, handler);
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}
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recv('elm_log', function(e) {console.log(e.value)});
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recv('elm_title', function(e) {document.title = e.value});
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recv('elm_redirect', function(e) {
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if (e.value.length > 0) { window.location = e.value; }
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});
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// If graphics are not enabled, escape early, skip over setting up DOM stuff.
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if (baseNode === null) return { send : send, recv : recv };
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var Render = ElmRuntime.use(ElmRuntime.Render.Element);
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// evaluate the given module and extract its 'main' value.
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signalGraph = module(elm).main;
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// make sure the signal graph is actually a signal, extract the visual model,
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// and filter out any unused inputs.
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var Signal = Elm.Signal(elm);
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if (!('recv' in signalGraph)) signalGraph = Signal.constant(signalGraph);
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visualModel = signalGraph.value;
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inputs = ElmRuntime.filterDeadInputs(inputs);
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var tuple2 = Elm.Native.Utils(elm).Tuple2;
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function adjustWindow() {
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if ('Window' in elm) {
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var w = baseNode.clientWidth;
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if (w !== elm.Window.dimensions.value._0) {
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notify(elm.Window.dimensions.id,
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tuple2(w, document.body === baseNode ?
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window.innerHeight : baseNode.clientHeight));
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}
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}
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}
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// Add the visualModel to the DOM
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var renderNode = Render.render(visualModel)
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baseNode.appendChild(renderNode);
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adjustWindow();
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// set up updates so that the DOM is adjusted as necessary.
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var update = Render.update;
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function domUpdate(value) {
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ElmRuntime.draw(function(_) {
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update(renderNode, visualModel, value);
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visualModel = value;
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adjustWindow();
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});
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return value;
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}
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signalGraph = A2(Signal.lift, domUpdate, signalGraph);
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return { send : send, recv : recv };
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};
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