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Object property defined with Object.defineProperty gets immediately evaluated #197
Description
Hello,
I hope this is the right place to ask...
I have a lot of components defined in different files and in my ruby code I'm loading them using the load function:
def initialize_js(config, locale = nil)
ctx = MiniRacer::Context.new
...
Dir.entries(path.join('auto', 'utils')).sort.each do |ent|
next if ent.start_with? '.'
if ent.end_with? '.js'
ctx.load(path.join('auto', 'utils', ent))
else
next unless File.directory?(path.join('auto', 'utils', ent))
Dir.entries(path.join('auto', 'utils', ent)).sort.each do |ent2|
next if ent2.start_with? '.'
ctx.load(path.join('auto', 'utils', ent, ent2))
end
end
end
...
ctx
endI moved outside of the component's init function the definition of a property:
Before:
utils.components.accessory_power_adapter = {
init: function(config, components) {
if(this.initialized) return;
Object.defineProperty(components, 'accessory_power_adapter', {
enumerable: true,
get: function() {
return this.component;
}.bind(utils.components.accessory_power_adapter)
});
// Initialize component
this._init_component(config, components);
this.initialized = true;
},
...
};After:
utils.components.accessory_power_adapter = {
init: function(config, components) {
if(this.initialized) return;
// Initialize component
this._init_component(config, components);
this.initialized = true;
},
...
};
Object.defineProperty(components, 'accessory_power_adapter', {
enumerable: true,
get: function() {
if(!this.initialized) {
throw 'call to components.accessory_power_adapter but the component is not initialized yet!';
}
return this.component;
}.bind(utils.components.accessory_power_adapter)
});And now I'm getting the exception
call to components.accessory_power_adapter but the component is not initialized yet!'
when I simply load the file in the context.
It looks to me that somehow after defining the property, the engine tries to access it and since the component is not initialized yet, I get the exception.
I don't know if this is a bug or it's the expected behavior, I'm running the same code in the browser and it's fine.
If I make the property not enumerable it doesn't happen, but I need the property to be enumerable, so the only workaround is to change the code to skip that check if I'm running the code server side:
Object.defineProperty(components, 'accessory_power_adapter', {
enumerable: true,
get: function() {
if(!this.initialized && !ruby) {
throw 'call to components.accessory_power_adapter but the component is not initialized yet!';
}
return this.component;
}.bind(utils.components.accessory_power_adapter)
});But I wanted to know why it is happening, if I've found a bug or I'm doing something wrong.
Thank you for your support!
mini_racer 0.4.0
libv8-node (15.14.0.0)
Activity
SamSaffron commentedon Apr 28, 2021
Can you craft a minimal repro in an rb file? Keep in mind load is a simple wrapper around eval.
afdev82 commentedon Apr 28, 2021
Yes, I saw the definition of the
loadmethod and at the end it callseval, there is also a comment there, I don't know if it's related to this issue.Please find example files attached.
define_property.zip
I saw that if I call the method
utils.components.accessory_power_adapter.initinside thedefine_property.js(before or afterObject.defineProperty) I don't have the exception. It doesn't help anyway, because I need to call the function in a different file.SamSaffron commentedon May 3, 2021
I think I know what is happening here. The last element in a script is returned to the caller of
eval.I guess a fix here would be to have load use a special flavor of
evalthat does not try to return the caller.A simple workaround would be a custom eval function:
Happy to fix up
loadhere so it does not evaluate.afdev82 commentedon May 3, 2021
Thank you for your answer :)
I'm glad to help if I can.
tisba commentedon Sep 29, 2022
Has this ever been implemented, @SamSaffron? Having
loadnot evaluate?