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Make hot reloading work with Elm 0.19.1 #87

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Make hot reloading work with Elm 0.19.1 #87

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f9589e4
Update hmr to a version that supports elm 0.19.1
asterite Aug 9, 2019
640e63e
fixup! Update hmr to a version that supports elm 0.19.1
asterite Aug 12, 2019
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66 changes: 51 additions & 15 deletions resources/hmr.js
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,35 @@ if (moduleHot.hot) {
};
}

// Elm 0.19.1 introduced a '$' prefix at the beginning of the symbols it emits,
// and we check for `List.map` because we expect it to be present in all Elm programs.
var elmVersion;
if (typeof elm$core$List$map !== 'undefined')
elmVersion = '0.19.0';
else if (typeof $elm$core$List$map !== 'undefined')
elmVersion = '0.19.1';
else
throw new Error("Could not determine Elm version");

function elmSymbol(symbol) {
try {
switch (elmVersion) {
case '0.19.0':
return eval(symbol);
case '0.19.1':
return eval('$' + symbol);
default:
throw new Error('Cannot resolve ' + symbol + '. Elm version unknown!')
}
} catch (e) {
if (e instanceof ReferenceError) {
return undefined;
} else {
throw e;
}
}
}

var instances = moduleHot.hot.data
? moduleHot.hot.data.instances || {}
: {};
Expand All @@ -51,7 +80,7 @@ if (moduleHot.hot) {
: 0;

if (Object.keys(instances).length === 0) {
console.log("[elm-hot] Enabled");
log("[elm-hot] Enabled");
}

var cancellers = [];
Expand All @@ -75,7 +104,7 @@ if (moduleHot.hot) {

// Second, kill pending tasks belonging to the old instance
if (cancellers.length) {
console.log('[elm-hot] Killing ' + cancellers.length + ' running processes...');
log('[elm-hot] Killing ' + cancellers.length + ' running processes...');
try {
cancellers.forEach(function (cancel) {
cancel();
Expand All @@ -86,6 +115,12 @@ if (moduleHot.hot) {
}
});

function log(message) {
if (moduleHot.hot.verbose) {
console.log(message)
}
}

function getId() {
return ++uid;
}
Expand Down Expand Up @@ -126,8 +161,8 @@ if (moduleHot.hot) {

function isFullscreenApp() {
// Returns true if the Elm app will take over the entire DOM body.
return typeof elm$browser$Browser$application !== 'undefined'
|| typeof elm$browser$Browser$document !== 'undefined';
return typeof elmSymbol("elm$browser$Browser$application") !== 'undefined'
|| typeof elmSymbol("elm$browser$Browser$document") !== 'undefined';
}

function wrapDomNode(node) {
Expand All @@ -148,6 +183,7 @@ if (moduleHot.hot) {
// behind their back and rudely put stuff in their DOM.
var dummyNode = document.createElement("div");
dummyNode.setAttribute("data-elm-hot", "true");
dummyNode.style.height = "inherit";
var parentNode = node.parentNode;
parentNode.replaceChild(dummyNode, node);
dummyNode.appendChild(node);
Expand Down Expand Up @@ -186,7 +222,7 @@ if (moduleHot.hot) {
}

function swap(Elm, instance) {
console.log('[elm-hot] Hot-swapping module: ' + instance.path);
log('[elm-hot] Hot-swapping module: ' + instance.path);

swappingInstance = instance;

Expand Down Expand Up @@ -218,28 +254,28 @@ if (moduleHot.hot) {
if (!handlers.length) {
return;
}
console.log('[elm-hot] Reconnect ' + handlers.length + ' handler(s) to port \''
log('[elm-hot] Reconnect ' + handlers.length + ' handler(s) to port \''
+ portName + '\' (' + instance.path + ').');
handlers.forEach(function (handler) {
elm.ports[portName].subscribe(handler);
});
} else {
delete instance.portSubscribes[portName];
console.log('[elm-hot] Port was removed: ' + portName);
log('[elm-hot] Port was removed: ' + portName);
}
});

Object.keys(instance.portSends).forEach(function (portName) {
if (portName in elm.ports && 'send' in elm.ports[portName]) {
console.log('[elm-hot] Replace old port send with the new send');
log('[elm-hot] Replace old port send with the new send');
instance.portSends[portName] = elm.ports[portName].send;
} else {
delete instance.portSends[portName];
console.log('[elm-hot] Port was removed: ' + portName);
log('[elm-hot] Port was removed: ' + portName);
}
});
} else {
console.log('[elm-hot] Module was removed: ' + instance.path);
log('[elm-hot] Module was removed: ' + instance.path);
}

swappingInstance = null;
Expand All @@ -260,7 +296,7 @@ if (moduleHot.hot) {
var unsubscribe = port.unsubscribe;
elm.ports[portName] = Object.assign(port, {
subscribe: function (handler) {
console.log('[elm-hot] ports.' + portName + '.subscribe called.');
log('[elm-hot] ports.' + portName + '.subscribe called.');
if (!portSubscribes[portName]) {
portSubscribes[portName] = [handler];
} else {
Expand All @@ -270,7 +306,7 @@ if (moduleHot.hot) {
return subscribe.call(port, handler);
},
unsubscribe: function (handler) {
console.log('[elm-hot] ports.' + portName + '.unsubscribe called.');
log('[elm-hot] ports.' + portName + '.unsubscribe called.');
var list = portSubscribes[portName];
if (list && list.indexOf(handler) !== -1) {
list.splice(list.lastIndexOf(handler), 1);
Expand Down Expand Up @@ -369,7 +405,7 @@ if (moduleHot.hot) {
var oldModel = swappingInstance.lastState;
var newModel = initialStateTuple.a;

if (typeof elm$browser$Browser$application !== 'undefined') {
if (typeof elmSymbol("elm$browser$Browser$application") !== 'undefined') {
// attempt to find the Browser.Navigation.Key in the newly-constructed model
// and bring it along with the rest of the old data.
var newKeyLoc = findNavKey(newModel);
Expand Down Expand Up @@ -406,13 +442,13 @@ if (moduleHot.hot) {
initialStateTuple.a = oldModel;

// ignore any Cmds returned by the init during hot-swap
initialStateTuple.b = elm$core$Platform$Cmd$none;
initialStateTuple.b = elmSymbol("elm$core$Platform$Cmd$none");
} else {
// capture the initial state for later
initializingInstance.lastState = initialStateTuple.a;

// capture Browser.application's navigation key for later
if (typeof elm$browser$Browser$application !== 'undefined') {
if (typeof elmSymbol("elm$browser$Browser$application") !== 'undefined') {
var navKeyLoc = findNavKey(initializingInstance.lastState);
if (!navKeyLoc) {
console.error("[elm-hot] Hot-swapping disabled for " + instance.path
Expand Down