51 lines
1.3 KiB
JavaScript
51 lines
1.3 KiB
JavaScript
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module.exports = function targetEnvironments() {
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var _targets = Object.create(null);
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var _activeCount = 0;
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var checkAllowed = function(target) {
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if (!(target in _targets)) {
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throw new Error(
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'Error accessing target "' + target + '". It is not in the list of allowed targets: ' +
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Object.keys(_targets));
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}
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};
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var updateActiveCount = function() {
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_activeCount = 0;
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for (target in _targets) {
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if (_targets[target]) _activeCount++;
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}
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};
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return {
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addAllowed: function(target, isActive) {
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_targets[target] = !!isActive;
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updateActiveCount();
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},
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removeAllowed: function(target) {
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delete _targets[target];
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updateActiveCount();
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},
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activate: function(target) {
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checkAllowed(target);
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_targets[target] = true;
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updateActiveCount();
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},
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deactivate: function(target) {
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checkAllowed(target);
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_targets[target] = false;
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updateActiveCount();
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},
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isActive: function(target) {
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checkAllowed(target);
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return _targets[target];
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},
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hasActive: function() { return _activeCount > 0; },
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someActive: function(targets) {
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for (var i = 0, ii = targets.length; i < ii; i++) {
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if (this.isActive(targets[i])) return true;
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}
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return false;
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}
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};
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};
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