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Why can't I connect this series of lodash calls?

This code:

  _(gameState.loot)
  .pick((value, key) -> key isnt "pickUpAnimations")
  .filter ((d) -> _.isArray (d))
  .reduce ((sum, d) -> sum.concat (d))

Gives me this error:

TypeError: 'undefined' is not a function (evaluating '(function(d) {

While this code is working fine:

  removedAnimations = _.pick(gameState.loot, (value, key) -> key isnt "pickUpAnimations")
  removedAnimations = _.filter removedAnimations, ((d) -> _.isArray (d))
  removedAnimations = _.reduce removedAnimations, ((sum, d) -> sum.concat (d))
  removedAnimations

It seems to me that they should do the same. The scheme gameState.lootlooks like this:

loot: {
  ttl: 6000
  slowBlinkWhenTtlLessThanPercent: 60
  fastBlinkWhenTtlLessThanPercent: 30
  resurrections: []
  gold: []
  health: []
  equipment: []
  pickUpAnimations: []
}

By the way, this is javascript generated from the first example:

return _(gameState.loot).pick(function(value, key) {
  return key !== "pickUpAnimations";
}).filter((function(d) {
  return _.isArray(d);
}).reduce((function(sum, d) {
  return sum.concat(d);
})));

I tried the @Blender suggestion:

  _(gameState.loot)
    .pick (value, key) -> key isnt "pickUpAnimations"
    .filter (d) -> _.isArray (d)
    .reduce (sum, d) -> sum.concat (d)

But this gave me this error:

>> TypeError: 'undefined' is not a function (evaluating '"pickUpAnimations".filter(function(d) {

This is what javascript looks like:

return _(gameState.loot).pick(function(value, key) {
  return key !== "pickUpAnimations".filter(function(d) {
    return _.isArray(d.reduce(function(sum, d) {
      return sum.concat(d);
    }));
  });
});
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2 answers

Here's the generated JavaScript with the best indentation:

_(gameState.loot).pick(function(value, key) {
    return key !== "pickUpAnimations";
}).filter(
    (function(d) {
        return _.isArray(d);
    }).reduce((function(sum, d) {
        return sum.concat(d);
    }))
);

As you can see, .filter (...and .filter(...do not match. Two errors are possible:

  • Remove the spaces between the method names and the opening parentheses:

    _(gameState.loot)
    .pick((value, key) -> key isnt "pickUpAnimations")
    .filter((d) -> _.isArray (d))
    .reduce((sum, d) -> sum.concat (d))

  • Remove the whole parentheses:

    _(gameState.loot)
    .pick (value, key) -> key isnt "pickUpAnimations"
    .filter (d) -> _.isArray (d)
    .reduce (sum, d) -> sum.concat (d)

, _.isArray:

    _(gameState.loot)
        .pick (value, key) -> key isnt "pickUpAnimations"
        .filter _.isArray
        .reduce (sum, d) -> sum.concat (d)
+9

:

_(gameState.loot).pick(function(value, key) {
  return key !== "pickUpAnimations";
}).filter((function(d) {
  return _.isArray(d);
}).reduce((function(sum, d) {
  return sum.concat(d);
})));

( . , :

(function(d) { return _.isArray(d); }).reduce(...

. , .

+2

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