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author | Matt A. Tobin <email@mattatobin.com> | 2018-02-10 02:51:36 -0500 |
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committer | Matt A. Tobin <email@mattatobin.com> | 2018-02-10 02:51:36 -0500 |
commit | 37d5300335d81cecbecc99812747a657588c63eb (patch) | |
tree | 765efa3b6a56bb715d9813a8697473e120436278 /toolkit/jetpack/sdk/ui/component.js | |
parent | b2bdac20c02b12f2057b9ef70b0a946113a00e00 (diff) | |
parent | 4fb11cd5966461bccc3ed1599b808237be6b0de9 (diff) | |
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Merge branch 'ext-work'
Diffstat (limited to 'toolkit/jetpack/sdk/ui/component.js')
-rw-r--r-- | toolkit/jetpack/sdk/ui/component.js | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/toolkit/jetpack/sdk/ui/component.js b/toolkit/jetpack/sdk/ui/component.js new file mode 100644 index 000000000..d1f12c95e --- /dev/null +++ b/toolkit/jetpack/sdk/ui/component.js @@ -0,0 +1,182 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ +"use strict"; + +// Internal properties not exposed to the public. +const cache = Symbol("component/cache"); +const writer = Symbol("component/writer"); +const isFirstWrite = Symbol("component/writer/first-write?"); +const currentState = Symbol("component/state/current"); +const pendingState = Symbol("component/state/pending"); +const isWriting = Symbol("component/writing?"); + +const isntNull = x => x !== null; + +const Component = function(options, children) { + this[currentState] = null; + this[pendingState] = null; + this[writer] = null; + this[cache] = null; + this[isFirstWrite] = true; + + this[Component.construct](options, children); +} +Component.Component = Component; +// Constructs component. +Component.construct = Symbol("component/construct"); +// Called with `options` and `children` and must return +// initial state back. +Component.initial = Symbol("component/initial"); + +// Function patches current `state` with a given update. +Component.patch = Symbol("component/patch"); +// Function that replaces current `state` with a passed state. +Component.reset = Symbol("component/reset"); + +// Function that must return render tree from passed state. +Component.render = Symbol("component/render"); + +// Path of the component with in the mount point. +Component.path = Symbol("component/path"); + +Component.isMounted = component => !!component[writer]; +Component.isWriting = component => !!component[isWriting]; + +// Internal method that mounts component to a writer. +// Mounts component to a writer. +Component.mount = (component, write) => { + if (Component.isMounted(component)) { + throw Error("Can not mount already mounted component"); + } + + component[writer] = write; + Component.write(component); + + if (component[Component.mounted]) { + component[Component.mounted](); + } +} + +// Unmounts component from a writer. +Component.unmount = (component) => { + if (Component.isMounted(component)) { + component[writer] = null; + if (component[Component.unmounted]) { + component[Component.unmounted](); + } + } else { + console.warn("Unmounting component that is not mounted is redundant"); + } +}; + // Method invoked once after inital write occurs. +Component.mounted = Symbol("component/mounted"); +// Internal method that unmounts component from the writer. +Component.unmounted = Symbol("component/unmounted"); +// Function that must return true if component is changed +Component.isUpdated = Symbol("component/updated?"); +Component.update = Symbol("component/update"); +Component.updated = Symbol("component/updated"); + +const writeChild = base => (child, index) => Component.write(child, base, index) +Component.write = (component, base, index) => { + if (component === null) { + return component; + } + + if (!(component instanceof Component)) { + const path = base ? `${base}${component.key || index}/` : `/`; + return Object.assign({}, component, { + [Component.path]: path, + children: component.children && component.children. + map(writeChild(path)). + filter(isntNull) + }); + } + + component[isWriting] = true; + + try { + + const current = component[currentState]; + const pending = component[pendingState] || current; + const isUpdated = component[Component.isUpdated]; + const isInitial = component[isFirstWrite]; + + if (isUpdated(current, pending) || isInitial) { + if (!isInitial && component[Component.update]) { + component[Component.update](pending, current) + } + + // Note: [Component.update] could have caused more updates so can't use + // `pending` as `component[pendingState]` may have changed. + component[currentState] = component[pendingState] || current; + component[pendingState] = null; + + const tree = component[Component.render](component[currentState]); + component[cache] = Component.write(tree, base, index); + if (component[writer]) { + component[writer].call(null, component[cache]); + } + + if (!isInitial && component[Component.updated]) { + component[Component.updated](current, pending); + } + } + + component[isFirstWrite] = false; + + return component[cache]; + } finally { + component[isWriting] = false; + } +}; + +Component.prototype = Object.freeze({ + constructor: Component, + + [Component.mounted]: null, + [Component.unmounted]: null, + [Component.update]: null, + [Component.updated]: null, + + get state() { + return this[pendingState] || this[currentState]; + }, + + + [Component.construct](settings, items) { + const initial = this[Component.initial]; + const base = initial(settings, items); + const options = Object.assign(Object.create(null), base.options, settings); + const children = base.children || items || null; + const state = Object.assign(Object.create(null), base, {options, children}); + this[currentState] = state; + + if (this.setup) { + this.setup(state); + } + }, + [Component.initial](options, children) { + return Object.create(null); + }, + [Component.patch](update) { + this[Component.reset](Object.assign({}, this.state, update)); + }, + [Component.reset](state) { + this[pendingState] = state; + if (Component.isMounted(this) && !Component.isWriting(this)) { + Component.write(this); + } + }, + + [Component.isUpdated](before, after) { + return before != after + }, + + [Component.render](state) { + throw Error("Component must implement [Component.render] member"); + } +}); + +module.exports = Component; |